CHAPTER X

ECONOMIC AND TECHNICAL

A. LICHENS AS FOOD.

_a._ FOOD FOR INSECTS, ETC. Some of the earlier botanists made careful

observations on the important place occupied by lichens in nature as

affording food to many small animals. In 1791 Jacques Brez[1226] wrote

his _Flore des Insectophyles_, and in the list of food-plants he includes

seven species of lichens. The “insects” that frequented these lichens

were species of the genera _Acarus_ (mites) and _Phalena_ (moths). A

few years later Persoon[1227] noted that lichens formed the main food

supply of many insects, slugs, etc. Zukal[1228], quoting from Otto Wilde

(_Die Pflanzen und Raupen Deutschlands_, Berlin, 1860), gives a list of

caterpillars that are known to feed on and destroy lichens.

A very considerable number of small creatures feed eagerly on lichens,

and traces of their depredations are constantly to be seen in the empty

fruit discs, and in the cortices eaten away in patches so as to expose

the white medulla. It has been argued by Zukal[1229] that the great

formation of acid substances in lichens is for shielding them against

the attacks of animals; Zopf[1230] on the contrary insists that these

substances afford the plants no real protection. He made a series of

experiments with snails, feeding them with slices of potato smeared with

pure lichen acids. Many snails ate the slices with great readiness even

when covered with bitter acids such as cetraric, or with those which

are poisonous for other animals such as rhizocarpic and pinastrinic.

The only acid they refused was vulpinic, which is said to be poisonous

for vertebrates. The crystals of the acids passed unchanged through the

alimentary canal of the snails, and were found in masses in the excreta.

They were undissolved, but, enclosed in slime, their sharp edges did no

damage to the digestive tract.

Stahl[1231] however upholds Zukal’s theory of the protective function

of lichen acids against the attacks of small animals. Some few snails,

caterpillars, etc., that are omnivorous feeders consume most lichens with

impunity, and the bitter taste seems to attract rather than repel them;

but many others he contends are certainly prevented from eating lichens

by the presence of the acids. He proved this by soaking portions of the

thalli of certain bitter species for about twenty-four hours in a one per

cent. soda solution, which was sufficiently strong to extract the acids.

He found that these treated specimens were in most cases preferred to

fresh portions that had been simply moistened with water.

Even the omnivorous snail, _Helix hortensis_, was several times observed

to touch the fresh thallus and then creep away, while it ate continuously

the soda-washed portion as soon as it came into contact with it. Calcium

Oxalate, on the other hand, formed no protection; omnivorous feeders

ate indifferently calcicolous lichens such as _Aspicilia calcarea_ and

_Lecanora saxicola_, whether treated with soda or not, but would only

accept lichens with acid contents, such as _Parmelia caperata_, _Evernia

prunastri_, etc., after they had been duly soaked.

Experiments were also made with wood-lice (_Oniscus murarius_), and with

earwigs (_Forficula auricularia_), and the result was the same: they

would only eat bitter lichens after the acids had been extracted by the

soda method. Stahl therefore concludes that acids must be regarded as

eminently adapted to protect lichens which otherwise, owing to their

slowness of growth, would scarcely escape extinction.

The gelatinous Collemaceae, as also _Nostoc_, the alga with which these

are associated, are unharmed by snails, etc., on account of their

slippery consistency when moist, which prevents the creatures from

getting a foothold on the thallus. These lichens however do not contain

acids, and if, when dry, they are reduced to powder and then moistened,

they are eagerly eaten both by snails and by wood-lice. _Peltigera

canina_, on account of a disagreeable odour it acquires on being chewed,

is avoided to a certain extent, but even so it is frequently found with

much of the thallus eaten away.

Hue[1232] in his study of Antarctic lichens, comments on the abundance

and perfect development of the lichens, especially the crustaceous

species, which cover every inch of rock surface. He ascribes this to

the absence of snails and insects which in other regions so seriously

interfere with the normal and continuous growth of these plants.

Snails do not eat lichens when they are dry and hard, but on damp or

dewy nights, and on rainy days, all kinds, both large and small, come

out of their shells and devour the lichen thalli softened by moisture.

Large slugs (_Limax_) have been seen devouring with great satisfaction

_Pertusaria faginea_, a bitter crustaceous lichen. The same _Limax_

species eats many different lichens, some of them containing very bitter

substances. Zopf[1233] observed that _Helix cingulata_ ate ten different

lichens, containing as many different kinds of acid.

Other creatures such as mites, wood-lice, and the caterpillars of

many butterflies live on lichens, though, with the exception of the

caterpillars, they eat them only when moist. Very frequently the

apothecial discs and the soredia are taken first as being evidently the

choicest portions. All lichens are, however, not equally palatable.

Bitter[1234] observed that the insect _Psocus_ (_Orthoptera_) had a

distinct preference for certain species, and restricted its attention to

them probably because of their chemical constitution. He noted that in

a large spreading thallus of _Graphis elegans_ on holly, irregular bare

spots appeared, due to the ravages of insects—probably _Psocus_. In other

places, the thallus alone had been consumed, leaving the rather hard

black fruits (lirellae) untouched. In time the thallus of _Thelotrema

lepadinum_, also a crustaceous lichen, invaded the naked areas, and

surrounded the _Graphis_ lirellae. The new comer was not to the taste of

the insects and was left untouched.

Petch[1235] says that lichens form the staple food of _Termes monoceros_,

the black termite of Ceylon. These ants really prefer algae, but as the

supply is limited they fall back on lichens, though they only consume

those of a particular type, or at a particular stage of development.

Those with a tough smooth cortex are avoided, preference being given

to thalli with a loose powdery surface. At the feeding ground the ants

congregate on the suitable lichens. With their mandibles they scrape

off small fragments of the thallus which they form into balls, varying

in size from 1·5 mm. to 2·5 mm. in diameter. The workers then convey

these to the nests in their mandibles. It would seem that they carry

about these balls of food, and allow the ants busy in the nest to nibble

off portions. Lichen balls are not used by termites as fungi are, for

“gardens.”

Other observations have been made by Paulson and Thompson[1236] in their

study of Epping Forest lichens: “Mites of the family Oribatidae must

be reckoned among the chief foes of these plants upon which they feed,

seeming to have a special predilection for the ripe fruits. We have had

excellent specimens of _Physcia parietina_ spoiled by hidden mites of

this family, which have eaten out the contents of the mature apothecia

after the lichens have been gathered. One can sometimes see small flocks

of the mites browsing upon the thallus of tree-dwelling lichens, like

cattle in a meadow.” The Oribatidae, sometimes called beetle-mites, a

family of Acarinae, are minute creatures familiar to microscopists. They

live chiefly on or about mosses, but Michael[1237] is of opinion that a

large number frequent these plants for the fungi and lichens which grow

in and about the mosses. In Michael’s _Monograph of British Oribatidae_,

four species are mentioned as true lichen-lovers, _Leiosoma palmicinetum_

found on _Peltigera canina_ and allied species; _Cepteus ocellatus_ and

_Oribata parmeliae_ which live on _Physciae_, the latter exclusively

on _Physcia_ (_Xanthoria_) _parietina_; and _Scutovertes maculatus_

which confines itself to lichens by the sea-shore. Another species,

_Notaspis lucorum_, frequents maritime lichens, but it is also found on

other substrata; while _Tegeocranus labyrinthicus_, though usually a

lichen-eating species, lives either on mosses or on lichens on walls.

Zopf[1238] reckoned twenty-nine species of lichens, mostly the larger

foliose and fruticose kinds, that were eaten by mites. Lesdain[1239] in

his observations on mite action notes that frequently the thallus round

the base of the perithecia of _Verrucaria_ sp. was eaten clean away,

leaving the perithecia solitary and extremely difficult to determine.

[Illustration: Fig. 126. 1, _Tetranychus lapidus_, enlarged; 2,

_Verrucaria calciseda_ with eggs _in situ_, slightly enlarged; 3 and 4,

eggs attached to lichen fruits, much magnified (after Wheldon).]

J. A. Wheldon[1240] found the eggs of a species of mite, _Tetranychus

lapidus_, attached to the fruits of _Verrucaria calciseda_, _Lecidea

immersa_ and _L. Metzleri_, calcicolous lichens of which the thallus not

only burrows deep down into the limestone, but the fruits form in shallow

excavated pits (Fig. 126). The eggs of this stone mite are found fairly

frequently on exposed limestone rocks, bare of vegetation, except for a

few crustaceous lichens. “There is usually a single egg, rarely two, in

each pit apparently attached to the old lichen apothecium. The eggs are

very attractive objects under a lens; they measure ·5 mm. in diameter,

and are disc-like with a central circular depression from which numerous

ridges radiate to the circumference, like the spokes of a wheel. When

fresh, they have a white pearly lustre, becoming chalk-white when dry and

old.” Wheldon’s observations were made in the Carnforth and Silverdale

district of West Lancashire.

A minute organism, _Hymenobolina parasitica_[1241], first described

by Zukal and doubtfully grouped among the mycetozoa, feeds, in the

plasmodium stage, on living lichens. The parasitic habit is unlike that

of true mycetozoa. It has recently been recorded from Aberdeenshire.

_b._ INSECT MIMICRY OF LICHENS. Paulson and Thompson[1242] give instances

of moth caterpillars, which not only feed on lichens, but which take on

the coloration of the lichens they affect, either in the larval or in

the perfect moth stage. “One of the most remarkable examples of this

protective resemblance to lichens is that of the larva of the geometrid

moth, _Cleora lichenaria_, which feeds upon foliose lichens growing upon

tree-trunks and palings, and being of a green-grey hue, and possessed of

two little humps on many of their body-segments, they so exactly resemble

the lichens in colour and appearance as to be extremely difficult of

detection.” Several instances are recorded of moths that resemble the

lichens on which they settle: perfect examples of such similarity

are exhibited at the Natural History Museum, South Kensington, where

_Teras literana_, _Moma orion_, and other moths are shown at rest on

lichen-covered bark from which they can hardly be distinguished.

Another curious instance of suggested mimicry is recorded by G.E.

Stone[1243]. He spotted a number of bodies on the bark of some sickly

elms in Massachusetts. They were about 1/8 of an inch in diameter “with a

dark centre and a drab foliaceous margin.” They were principally lodged

in the crevices of the bark and Stone collected them under the impression

that they were the apothecia of a lichen most nearly resembling those of

_Physcia hypoleuca_. Some of the bodies were even attached to the thallus

of a species of _Physcia_; others were on the naked bark and had every

appearance of lichen fruits. Only closer examination proved their insect

nature, and they were identified as belonging to a species _Gossypina

Ulmi_, an elm-leaf beetle common in Europe where it causes a disease of

the tree. It had been imported into the United States and had attacked

American elms.

It is stated by Tutt[1244] that the larvae of many of the Psychides

(_Lepidoptera_) live on the lichens of trees and walls, such as

_Candelaria concolor_, _Xanthoria parietina_, _Physcia pulverulenta_

and _Buellia canescens_, and that their larvae pupate on their feeding

grounds. Each species makes a “case” peculiar to itself, but those of the

lower families are usually covered externally with grains of sand, scraps

of lichens, etc. The “case” of _Narcyria monilifera_, for instance, is

somewhat raised on a flat base and is obscured with particles of sand

and yellow lichen, giving the whole a yellow appearance. That of _Luffia

lapidella_ is roughly conical and is held up at an angle of 30° to 45°

when the larva moves. The “cases” of _Bacotia sepium_ are always upright;

they measure about 5·5 mm. in height and 2·75 mm. in width and present a

hoary appearance from the minute particles of lichen with which they are

covered, so that the structure is not unlike the podetium of a _Cladonia_.

_c._ FOOD FOR THE HIGHER ANIMALS. It has been affirmed, especially by

Henneguy, that many lichens, if deprived of the bitter principle they

contain, by soaking in water, or with the addition of sodium or potassium

carbonate, might be used with advantage as fodder for animals. He cites

as examples of such, _Lobaria pulmonaria_, _Evernia prunastri_, _Ramalina

fraxinea_, _R. farinacea_, and _R. fastigiata_, all of which grow

abundantly on trees, and owe their nutritive quality to the presence of

lichenin, a carbohydrate allied to starch.

[Illustration: Fig. 127. _Cladonia rangiferina_ Web. (S. H., _Photo._).]

_Cladonia rangiferina_ (Fig. 127), the well-known “reindeer moss,” is,

however, the lichen of most economic importance, as food for reindeer,

cattle, etc. It is a social plant and forms dense tufts and swards of

slender, much branched, hollow stalks of a greenish-grey colour which may

reach a height of twelve inches or even more; the stalks decay slowly

at the base as they increase at the apex, so that very great length is

never attained. In normal conditions they neither wither nor die, and

growth continues indefinitely. It is comparatively rare in the northern

or hilly regions of the British Isles, and is frequently confused with

the somewhat smaller species _Cl. sylvatica_ which is very common on our

moorlands, a species which Zopf[1245] tells us reindeer absolutely refuse

to eat.

The true reindeer moss is abundant in northern countries, more especially

in forest regions[1246] and in valleys between the tundra hills which

are more or less sheltered from the high winds; it is independent of the

substratum and flourishes equally on barren sand and on wet turf; but

grows especially well on soil devastated by fire. For long periods it

may be covered with snow without injury and the reindeer are accustomed

to dig down with horns and hoofs in order to reach their favourite food.

Though always considered as peculiarly “reindeer” moss, deer, roebuck

and other wild animals, such as Lemming rats[1247], feed on it largely

during the winter. In some northern districts it is collected and stored

as fodder for domestic cattle; hot water is poured over it and it is

then mixed with straw and sprinkled with a little salt. Johnson[1248]

has reported that the richness of the milk yielded by the small cows of

Northern Scandinavia is attributed by some to their feeding in great

measure on the “reindeer moss.”

[Illustration: Fig. 128. _Cetraria islandica_ Ach. (S. H., _Photo._).]

When _Cladonia rangiferina_ is scarce, a few other lichens[1249] are made

use of, _Alectoria jubata_, a brownish-black filamentous tree-lichen

being one of the most frequent substitutes. _Stereocaulon paschale_,

which grows in large dense tufts on the ground in mountainous regions,

is also eaten by reindeer and other animals; and Iceland moss, _Cetraria

islandica_, is stored up in large quantities by the Icelanders and used

as fodder. Willemet[1250] reports it as good for horses, oxen, cows and

pigs.

It is interesting to recall a discovery of prehistoric remains at the

Abbey of Schussenried on the Lake of Constance and described by F.

Keller[1251]: under successive beds of peat and crumbly tufa, there was

found a layer, 3 feet thick, containing flints, horns of reindeer and

bones of various animals, and, along with these, masses of reindeer moss;

a sufficient proof of its antiquity as a fodder-plant.

_d._ FOOD FOR MAN. Lichens contain no true starch nor cellulose, but the

lichenin present in the cell-walls of the hyphae has long been utilized

as a food substance. It is peculiarly abundant in _Cetraria islandica_

(Fig. 128), which grows in northern countries, covering great stretches

of ground with its upright strap-shaped branching fronds of varying

shades of brown. In more southern lands it is to be found on high hills

or on upland moors, but in much smaller quantities. Commercial “Iceland

moss” is supplied from Sweden, Norway or Iceland. In the last-named

country the inhabitants harvest the lichen preferably from bare stony

soil where there is no admixture of other vegetation. They revisit the

locality at intervals of three years, the time required for the lichen

to grow to a profitable size; and they select the wet season for the

ingathering of the plants as they are more easily detached when they are

wet. If the weather should be dry, they collect it during the night.

When gathered it is cleansed from foreign matter and washed in water to

remove as much as possible of the bitter principle. It is then dried and

reduced to powder. When required, the powder is put to macerate in water

for 24 hours, or it is soaked in a weak solution of soda or of carbonate

of potassium, by which means the bitter cetraric acid is nearly all

eliminated. When boiled[1252] it yields a jelly which forms the basis of

various light and easily digested soups or of other delicacies prepared

by boiling in milk, which have been proved to be valuable for dyspeptics

or sufferers from chest diseases. The northern nations also make the

powder into bread, porridge or gruel. Johnson[1253] states in his account

of “Useful Plants” that considerable quantities of Iceland moss were

formerly employed in the manufacture of sea biscuit, and that ship’s

bread mixed with it was said to be less liable to the attacks of weevil

than when made from wheat flour only.

An examination of the real food value of the mucilaginous extract from

“Iceland moss” has been made by several workers. Church[1254] states

that for one part of flesh formers, there are eight parts of heat-givers

reckoned as starch. Brown[1255] isolated the two carbohydrates, lichenin

and isolichenin. The former, a jelly which yields on hydrolysis a large

quantity of a reducing sugar, dextrose, ferments with yeast and gives no

phloroglucin reaction; it is unaffected by digestion and probably does

not form glycogen. Iso-lichenin is much less abundant and resembles

soluble starch, but on digestion yields only dextrins—no sugar. It may

be concluded, judging from the chemical nature of the mucilage, from the

resistance of its constituents to digestion and from the small amount

present in the jelly, that its nutritive value is practically nil[1256].

It has been stated that “reindeer moss” in times of food scarcity is

powdered and mixed with “Iceland moss” and rye to make bread in North

Finland. Johnson confirms this and cites the evidence of a Dr Clarke

that: “to our surprise we found we might eat of it with as much ease as

of the heart of a fine lettuce. It tasted like wheat-bran, but after

swallowing it, there remained in the throat and upon the palate a gentle

heat, or sense of burning, as if a small quantity of pepper had been

mixed with the lichen.”

The Egyptians[1257] have used _Evernia prunastri_, more rarely _E.

furfuracea_, in baking. In the eighteenth century fermentative agents

such as yeast were unknown to them, and these lichens, which were

imported from more northern lands, were soaked in water for two hours and

the solution then mixed with the flour to give a much appreciated flavour

to the unleavened bread.

In India[1258] a species of _Parmelia_ (near to _P. perlata_) known in

the Telegu language as “rathapu” or rock-flower has been used as a food,

generally prepared as a curry, by the natives in the Bellary district

(Madras Presidency), and is esteemed as a delicacy. It is also used

medicinally. The collecting of rathapu is carried on during the hot

weather in April and May, and forms a profitable business.

A note has been published by Calkins[1259], on the authority of

a correspondent in Japan, that large quantities of _Endocarpon_

(_Dermatocarpon_) _miniatum_ (Fig. 56) are collected in the mountains of

that country for culinary purposes, and largely exported to China as an

article of luxury. The local name is “iwataka,” meaning stone-mushroom.

Properly prepared it resembles tripe. It is possibly the same lichen

under a different name, _Gyrophora esculenta_, which is described by

Manabu Miyoshi[1260] as of great food value in Japan where it is known

as “iwatake.” It is a greyish-brown leathery “monophyllous” plant of

somewhat circular outline and fairly large size, measuring 3 to 13 cm.

across. Fertile specimens are rare, and are smaller than the sterile.

It grows generally on the steep declivities of damp granitic rocks and

is common in various districts of Japan, being especially abundant on

such mountains as Kiso, Nikko, Kimano, etc. The face of the precipices

is often thickly covered with the lichen growth. The inhabitants collect

the plants in large quantities. They dry them and send them to the towns,

where they are sold in all vegetable stores; some are even exported to

other countries. These lichens are not bitter to the taste, nor are they

irritating as are other species of the genus. They are on the contrary

quite harmless and are much relished by the Japanese on account of their

agreeable flavour, in spite of their being somewhat indigestible. Though

only determined scientifically in recent times, this edible lichen has

long been known, and the risks attending its collection have frequently

been described in Old Chinese and Japanese writings.

[Illustration: Fig. 129. _Gyrophora polyrhiza_ Koerb. (S. H., _Photo._,

reduced).]

Other species of _Gyrophora_ including _G. polyrhiza_ (Fig. 129) and

_Umbilicaria_, black leathery lichens which grow on rocks in northern

regions, have also been used as food. They are the “Tripe de Roche” or

Rock Tripe of Arctic regions, a name given to the plants by Canadian

fur-hunters. They have been eaten by travellers and others in desperate

straits for food; but though to a certain extent nutritious, they are

bitter and nauseous, and cause severe internal irritation if the bitter

acids are not first extracted by boiling or soaking.

Of more historical interest is the desert lichen _Lecanora esculenta_,

supposed to be the manna[1261] of the Israelites, and still called “bread

from heaven.” Eversmann[1262] wrote an account of its occurrence and

qualities, and fuller information was given by Berkeley[1263]: when mixed

with meal to a third of its weight it is made into bread and eaten by the

desert tribes. It grows abundantly in North Africa and in many parts of

Western Asia, on the rocks or on soil. It is easily broken off and driven

into heaps by the wind; and has been reported as covering the soil to a

depth of 15 cm. to 20 cm. with irregular contorted lumps varying in size

from a pea to a small nut (Fig. 130). Externally these are clear brown

or whitish; the interior is white, and consists of branching interlaced

hyphae, with masses of calcium oxalate crystals, averaging about 60 per

cent. or more of the whole substance.

[Illustration: Fig. 130. _Lecanora esculenta_ Eversm. Loose nodules of

the sterile thallus.]

A still more exhaustive account is given by Visiani[1264], who quotes

the experience of a certain General Jussuf, who had tested its value in

the Sahara as food for his soldiers. When bread was made from the lichen

alone it was friable and without consistency; when mixed with a tenth

portion of meal it was similar to the soldiers’ ordinary bread, and had

something of the same taste. The General also gave it as fodder to the

horses, some of them being nourished with the lichen and a mixture of

barley for three weeks without showing any ill effects. It is also said

that camels, gazelles and other quadrupeds eat it with advantage, though

it is in any case a very defective food.

A remarkable deposit of the lichen occurred in recent times in

Mesopotamia during a violent storm of hail. After the hail had

melted, the ground was seen to be covered, and specimens were sent to

Errera[1265] for examination. He identified it as _Lecanora esculenta_.

In his opinion two kinds of manna are alluded to in the Bible: in one

case (Exodus xvi.) it is the sweet gum exuded from the tamarisk that is

described; the other kind (Numbers xi.), he thinks, plainly refers to the

lichen. He considers that its nutritive value must be very low, and it

can only be valued as food in times of famine.

B. LICHENS AS MEDICINE

_a._ ANCIENT REMEDIES. An interesting note has been published by

Müller-Argau[1266] which seems to trace back the medicinal use of lichens

to a very remote age. He tells us that Dr Schweinfurth, the distinguished

traveller, who made a journey through the valley of the Nile in 1864,

sent to him from Cairo a piece of lichen thallus found in a vase along

with berries of _Juniperus excelsa_ and of _Sapindus_, with some other

undetermined seeds. The vase dated from the 18th Dynasty (1700 to 1600

B.C.), and the plants contained in it must thus have lain undisturbed

over 3000 years. The broken pieces of the lichen thallus were fairly

well preserved; they were extremely soft and yellowish-white and almost

entirely decorticate, but on the under surfaces there remained a few

black patches, which, on microscopical examination, enabled Müller

to identify them as scraps of _Evernia furfuracea_. This lichen does

not grow in Egypt, but it is still sold there along with _Cetraria

islandica_ and some other lichens as foreign drugs. Dr Schweinfurth

considered his discovery important as proving the use of foreign remedies

by the ancient Egyptians.

_b._ DOCTRINE OF “SIGNATURES.” In the fifteenth century A.D. there was

in the study and treatment of disease a constant attempt to follow the

guidance of nature. It was believed that Providence had scattered here

and there on plants “signatures,” or resemblances more or less vague to

parts of the human body, or to the diseases to which man is subject, thus

indicating the appropriate specific.

[Illustration: Fig. 131. _Parmelia saxatilis_ Ach. (S. H., _Photo._).]

Lichens among other plants in which any “signature” could be detected

or imagined were therefore constantly prescribed: the long filaments of

_Usnea barbata_ were used to strengthen the hair; _Lobaria pulmonaria_,

the true lung-wort, with its pitted reticulate surface (Fig. 72), was

marked as a suitable remedy for lung troubles; _Xanthoria parietina_

being a yellow lichen was supposed to cure jaundice, and _Peltigera

aphthosa_, the thallus of which is dotted with small wart-like

tubercles[1267], was recommended for children who suffered from the

“thrush” eruption.

The doctrine reached the height of absurdity in the extravagant value

set on a lichen found growing on human skulls, “Muscus cranii humani”

or “Muscus ex cranio humano.” There are a number of lichens that grow

indifferently on a variety of substances, and not infrequently on bones

lying in the open. This skull lichen[1268], _Parmelia saxatilis_ (Fig.

131) or some other, was supposed to be worth its weight in gold as a cure

for epilepsy. Parkinson[1269] tells us in all confidence “it groweth

upon the bare scalps of men and women that have lyen long ... in former

times much accounted of because it is rare and hardly gotten, but in our

own times much more set by, to make the ‘Unguentum Sympatheticum’ which

cureth wounds without the local application of salves ... but as Crollius

hath it, it should be taken from the sculls of those that have been

hanged or executed for offences.” Ray[1270] says that the same gruesome

plant “is celebrated by several authors as useful in haemorrhages and

is said to be an ingredient of the famous ‘Unguentum Armarium[1271],’

reported to have been invented by Paracelsus.” Another lost ointment!

_c._ CURE FOR HYDROPHOBIA. Still another lichen to which extraordinary

virtue was ascribed, was the very common ground species _Peltigera

canina_ (Fig. 54), a preparation of which was used in the cure of rabies.

Dillenius[1272] has published in full the prescription as “A certain Cure

for the Bite of a Mad Dog” which was given to him by a very celebrated

physician of that day, Dr Richard Mead, who had found it effective:

“Let the patient be blooded at the arm, nine or ten ounces. Take of

the herb called in Latin _Lichen cinereus terrestris_, in English

Ash-coloured ground liverwort, clean’d, dry’d and powder’d half an ounce.

Of black pepper powder’d two drachms.

“Mix these well together and divide the Powder into four Doses, one

of which must be taken every Morning, fasting, for four Mornings

successively in half a Pint of Cow’s Milk warm. After these four Doses

are taken, the Patient must go into the cold bath, or a cold Spring or

River, every Morning fasting, for a Month. He must be dipt all over but

not stay in (with his head above water) longer than half a minute, if the

Water be very cold. After this he must go in three Times a Week for a

Fortnight longer.”

Lightfoot[1273], some forty years later, refers to this medicine as “the

once celebrated ‘Pulvis antilyssus,’ much recommended by the great Dr

Mead.” He adds that “it is much to be lamented that the success of this

medicine has not always answered the expectation. There are instances

where the application has not prevented the Hydrophobia, and it is very

uncertain whether it has been at all instrumental in keeping off that

disorder.” Belief in the efficacy of the powder died out before the end

of the century but the echo of the famous remedy remains in the name

_Peltigera canina_, the dog lichen.

_d._ POPULAR REMEDIES. Lichens with very few exceptions are non-poisonous

plants. They owed their repute as curative herbs to the presence in

the thallus of lichenin and of some bitter or astringent substances,

which, in various ailments, proved of real service to the patient,

though they have now been discarded in favour of more effective drugs.

Some of them, on account of their bitter taste, were frequently used

as tonics to replace quinine in attacks of fever. Several species of

_Pertusaria_, such as the bitter _P. amara_ (Fig. 132), and of _Cladonia_

as well as _Cetraria islandica_ (Fig. 128), were recommended in cases

of intermittent fever; species of _Usnea_ and others, as for instance

_Evernia furfuracea_, were used as astringents in haemorrhages; others

were given for coughs, _Cladonia pyxidata_ (Fig. 69) being supposed to be

specially valuable in whooping cough.

[Illustration: Fig. 132. _Pertusaria amara_ Nyl. on bark (S. H.,

_Photo._).]

One of the most frequently prescribed lichens was the tree lung-wort

(Lobaria pulmonaria) (Fig. 72). It was first included among medical

plants by Dorstenius[1274], a Professor at Marburg; he gives a good

figure and supplies directions for its preparation as a cure for chest

complaints. The doctrine of “signatures” influenced practitioners in its

favour, but it contains lichenin which acts as an emollient. In England,

it was taken up by the famous Dr Culpepper[1275], who, however, believed

in astrology even more than in signatures. He says: “it is of great use

with many physicians to help the diseases of the lungs and for coughs,

wheesings and shortness of breath which it cureth both in man and beast.”

He adds that “Jupiter seems to own the herb.” A century later we find Dr

John Hill[1276], who was a physician as well as a naturalist, stating

that the great tree lung-wort has been at all times famous in diseases

of the breast and lungs, but by that time “it was not much used owing to

change in fashions.”

The only lichen that has stood the test of time and experience as a real

remedy is _Cetraria islandica_, and even the “Iceland moss” is now rarely

prescribed. The first mention in literature of this famous plant occurs

in Cordus[1277] as the _Muscus_ with crisp leaves. Some years later it

figures among the medicinal plants in Sibbald’s[1278] _Chronicle of the

Scottish Flora_, and Ray[1279] wrote of it about the same time as being

known for its curative and alimentary properties. It was Linnaeus[1280],

and later Scopoli[1281], who gave it the important place it held so long

in medicine. It has been used with advantage in many chronic affections

as an emollient and tonic. Cramer[1282] in a lengthy dissertation

gathered together the facts pertaining to its use as a food, a medicine

and for dyeing, and he gives recipes he had himself prescribed with

marked success in many different maladies. It has been said that if

“Iceland moss” accomplished all the good it was alleged to do, it was

indeed a “Divine gift to man.”

The physiological action of cetrarin (acid principle of the lichen) on

living creatures has been studied by Kobert[1283] and his pupils. It

has not any poisonous effect when injected into the blood, nor does

it work any harm when taken into the stomach even of small animals,

so that it may be safely given to the most delicate patients. Nearly

always after small doses peristaltic movements in the intestines are

induced which indicate that as a drug it might be of service in the case

of enfeebled organs. In larger doses it may cause collapse in animals,

but if administered as free cetraric acid it passes through the stomach

unchanged to become slowly and completely dissolved in the intestine. The

mucous membrane of the intestine of animals that had been treated with an

overdose, was found to be richer in blood so that it seems as if cetrarin

might be of service in chlorosis and in assisting digestion.

Cetrarin has also been proved to be a nerve excitant which might be used

with advantage in mental maladies.

C. LICHENS AS POISONS

Though the acid substances of lichens are most of them extremely

irritating when taken internally, very few lichens are poisonous.

Keegan[1284] writing on this subject considers this quality of

comparative innocuousness as a distinctive difference between fungi and

lichens and he decides that it proves the latter to be higher organisms

from a physiological point of view: “the colouring matters being true

products of deassimilation, whereas those of fungi are decomposition or

degradation waste products of the albuminoids akin to alkaloids.”

The two outstanding exceptions to this general statement are the two

Alpine species _Letharia vulpina_ and _Cetraria pinastri_. The former

contains vulpinic acid in the cortical cells, the crystals of which are

lemon-yellow in the mass. _Cetraria pinastri_ produces pinastrinic acid

in the hyphae of the medulla and the crystals are a beautiful orange or

golden yellow.

These lichens, more especially _Letharia vulpina_, have been used by

Northern peoples to poison wolves. Dead carcasses are stuffed with a

mixture of lichen and powdered glass and exposed in the haunts of wolves

in time of frost. Henneguy[1285], who insists on the non-poisonous

character of all lichens, asserts that the broken glass is the fatal

ingredient in the mixture, but Kobert[1286], who has proved the poisonous

nature of vulpinic acid, says that the wounds caused by the glass render

the internal organs extremely sensitive to the action of the lichen.

Kobert, Neubert[1287] and others have recorded the results of experiments

on living animals with these poisons. They find that _Letharia vulpina_

either powdered or in solution has an exciting effect on the mucous

membrane. Elementary organisms treated with a solution of the lichen

succumbed more quickly than in a solution of the acid as a salt. Kobert

concluded that vulpinic acid is a poison of protoplasm.

He further tested the effect of the poison on both cold- and warm-blooded

animals. Administered as a sodium salt, 4 mg. proved fatal to frogs.

The effect on warm-blooded animals was similar. A sodium salt, whether

swallowed or administered as subcutaneous or intravenous injections, was

poisonous. Cats were the most sensitive—hedgehogs the least—of all the

animals that were subjected to the experiments. Volkard’s[1288] synthetic

preparation of vulpinic acid gave the same results as the solution

directly extracted from the lichens.

D. LICHENS USED IN TANNING, BREWING AND DISTILLING

The astringent property in _Cetraria islandica_ and in _Lobaria

pulmonaria_ has been made use of in tanning leather. The latter lichen

grows commonly on oak and could hardly be gathered in sufficient quantity

to be of commercial importance. Like many other lichens it develops very

slowly. _Lobaria pulmonaria_ has also been used to replace hops in the

brewing of beer. Gmelin[1289] in his journey through Siberia visited a

monastery at Ussolka where the monks employed it for this purpose. The

beer tasted exactly like that made with hops, but was more intoxicating.

The lichen in that country grew on pine-trees.

Lichens have in more modern times been used in the preparation of

alcohol. The process of manufacture was discovered by Roy of Tonnerre,

early in the nineteenth century, and was described by Léorier[1290].

It was further improved by Stenberg[1291], a Professor of Chemistry in

Stockholm. Roy had worked with _Physcia ciliaris_, _Ramalina fraxinea_,

_R. fastigiata_, _R. farinacea_ and _Usnea florida_, but Stenberg and

distillers after his time[1292] made more use of _Cladonia rangiferina_

(Fig. 127), _Cetraria islandica_ (Fig. 128) and _Alectoria jubata_.

By treatment with weak sulphuric or nitric acid the lichenin of the

thallus is transformed into glucose which on fermentation forms alcohol.

Stenberg found that 68 per cent. of the weight in _Cladonia rangiferina_

was a “sugar” from which a good brandy could be prepared: a kilogramme of

the lichens furnished half a litre of alcohol. The Professor followed up

his researches by establishing a distillery near Stockholm. His papers

contain full instructions as to collecting and preparing the plants.

Henneguy[1293], writing in 1883, stated that the fabrication of alcohol

from lichens was then a large and increasing industry in Sweden. The

whole industry seems, however, to have fallen into disuse very soon:

Wainio[1294], quoting Hellbom[1295], states that the various distilleries

were already closed in 1884, because of the exhaustion of the lichen in

the neighbourhood, and the impossibility of obtaining sufficient supplies

of such slow-growing plants.

E. DYEING PROPERTIES OF LICHENS

_a._ LICHENS AS DYE-PLANTS. Knowledge as to the dyeing properties

of lichens dates back to a remote antiquity. It has been generally

accepted that lichen-colours are indicated by the prophet Ezekiel in his

denunciation of Tyre: “blue and purple from the Isles of Elishah was that

which covered thee.” Theophrastus describes certain plants as growing

in Crete, and being used to dye wool, etc., and Pliny in his _Phycos

Thalassion_ is also understood as referring to the lichen _Roccella_,

“with crisp leaves, used in Crete for dyeing garments.”

Information as to the dyeing properties of certain lichens is given in

most of the books or papers dealing with these plants from the herbals

onwards. Hoffmann[1296] devoted a large part of his _Commentatio de

vario Lichenum usu_ to the dye-lichens, and, illustrating his work, are

a series of small rectangular coloured blocks representing samples of

woollen cloth dyed with different lichens. There are seventy-seven of

these samples with the colour names used by French dyers.

An important treatise on the subject translated into French was also

contributed by Westring[1297]. He desired to draw attention to the

tinctorial properties of lichens other than the _Roccellae_ which do

not grow in Sweden. The Swedes, he states, already used four to six

lichens as dye-plants, but only for one colour. He demonstrated by his

improved methods that other colours and of finer tint could be obtained.

He describes the best methods both of extraction and of dyeing, and

then follows with an account of the different lichens likely to be of

service. The treatise was subsequently published at greater length in

Swedish[1298] with twenty-four very fine coloured illustrations of the

lichens used, and with sample blocks of the colours to be obtained.

_b._ THE ORCHIL LICHEN, ROCCELLA. The value of _Roccella_ as a dye-plant

had been lost sight of until it was accidentally rediscovered, early in

the fourteenth century, by a Florentine merchant called Federigo. He

introduced its use into Florence, and as he retained the industry in

his own hands he made a large fortune, and founded the family of the

Orcellarii, called later the Rucellarii or Rucellai, hence the botanical

name, _Roccella_. The product was called _orseille_ for which the

English name is orchil or archil. Another origin suggested for orchil

is the Spanish name of the plant, _Orcigilia_. There are a number of

different species that vary in the amount of dye-product. Most of them

grow on rocks by the sea-side in crowded bluish-grey or whitish tufts of

strap-shaped or rounded stiff narrow fronds varying in length up to about

six inches or more. The main supply of “weeds” came from the Levant until

the fifteenth century when supplies were obtained from the Canaries (long

considered to produce the best varieties), Cape Verd and the African

coasts. The geographical distribution of the _Roccellae_ is very wide:

they grow on warm sea-coasts all over the globe, more particularly in

Angola, the Cape, Mozambique, Madagascar, in Asia, in Australia, and in

Chili and Peru.

Zopf[1299] has proved the existence of two different colouring substances

among the Roccellas: in _R. fuciformis_ (Fig. 57) and _R. fucoides_

(both British species), in _R. Montagnei_ and _R. peruensis_ the

acid present is erythrin; in _R. tinctoria_, _R. portentosa_ and _R.

sinuensis_ it is lecanoric acid. In _R. tinctoria_ (Fig. 133), according

to Ronceray[1300], the acid is located chiefly in the gonidial layer and

the soredia but is absent from the cortex and centre. In _R. portentosa_

it is abundant in the cortex and central layer, while scarcely to be

detected in the gonidial layer, and it is wanting altogether in the

soredia. In _R. Montagnei_ it is chiefly found in the cortex and the

gonidial layer, and is absent from the soredia and from the medulla.

_c._ PURPLE DYES: ORCHIL, CUDBEAR AND LITMUS. Orseille or orchil is

formed not only from erythrin and lecanoric acid (orseillic acid), but

also from erythrinic, gyrophoric, evernic and ramalic acids[1301] and may

be obtained from any lichen containing these substances. By the action

of ammonia the acids are split up into orcin and carbonic acid. In time,

under the influence of ammonia and the oxygen of the air[1302], orcin

becomes orcein which is the colouring principle of orchil; the perfecting

of the process may take a month. The dye is used for animal fibres such

as wool and silk; it has no effect on cotton.

There are several different preparations on the market, chiefly obtained

from France and Holland; orchil or orseille in the form of a solution,

cudbear (persio of Germany) almost the same, but manufactured into a

violet-reddish powder, and litmus (tournesol of France) which is prepared

in a slightly different manner. At one time the lichen, broken into small

pieces, was soaked in urine; a fermentation process was set up, then lime

and potash with an admixture of alum were added. The mass of material

when ready was pressed into cubes and dried in the air. Commercial litmus

contains three substances, erythrolein, erythrolitmin and azolitmin; the

last named, which is the true litmus, is a dark brown amorphous powder

soluble in water, and forming a blue solution with alkalies.

[Illustration: Fig. 133. _Roccella tintoria_ Ach. From the Cape of Good

Hope.]

An aqueous solution of litmus when exactly neutralized by an acid

is violet coloured; it becomes red with the smallest trace of free

acid, or blue with free alkali. Litmus paper is prepared by steeping

specially prepared unsized paper in the dye solution. It is as a ready

and sensitive indicator of acidity or alkalinity that litmus is of so

much value. According to Zopf[1303] it is also used as a blueing agent

in washing and as a colouring of wine. Litmus is chiefly manufactured

in Holland. Still another substance somewhat differently prepared from

the same lichens is sold as French purple, a more brilliant and durable

colour than orchil.

[Illustration: Fig. 134. _Lecanora tartarea_ Ach. (S. H., _Photo._).]

_d._ OTHER ORCHIL LICHENS. Though species of _Roccella_ rank first

in importance as dye-plants, purple and blue colours are obtained,

as indicated above, from other very different lichens. Lindsay[1304]

extracted orchil from about twenty species. Those most in use in northern

countries are on the whole less rich in colouring substances; they

are: _Umbilicaria pustulata_, species of _Gyrophora_, _Parmelia_ and

_Pertusaria_, and above all _Lecanora tartarea_ (Fig. 134). The last

named, one of the hardiest and most abundant of rock- or soil-lichens,

is chiefly used in Scotland and Sweden (hence the name “Swedish moss”)

to furnish a red or crimson dye. In Scotland all dye-lichens are called

“crottles,” but the term “cudbear” was given to _Lecanora tartarea_

(either the lichen or the dye-product); it was acquired from a corrupt

pronunciation of the Christian name of Dr Cuthbert Gordon, a chemist,

who, according to Bohler[1305], obtained a patent for his process

of producing the dye, or who first employed it on a great scale in

Glasgow. Johnson[1306] remarks that the colour yielded by cudbear, if

well prepared, is a fine, clear, but not very bright purple. It is, he

alleges, not permanent. Like other orchil substances it is without effect

on cotton or linen.

_e._ PREPARATION OF ORCHIL. A general mode of treatment of dye-lichens

recommended by Lauder Lindsay[1307] for home production of orchil,

cudbear and litmus is as follows:

1. Careful washing, drying and cleansing to separate earthy and

other impurities.

2. Pulverization into a coarse or fine pulp with water.

3. Repeated addition of ammoniacal liquor of a certain strength,

obtainable from several sources (_e.g._ putrid urine, gas liquor,

etc.).

4. Frequent stirring of the fermenting mass so as to ensure full

exposure of every part thereof to the action of atmospheric

oxygen.

5. Addition of alkalies in some cases (_e.g._ potash or soda),

to heighten or modify colour; and of chalk, gypsum and other

substances to impart consistence.

_f._ BROWN AND YELLOW DYES. The extracting of these colours from lichens

is also a very old industry. Linnaeus found during his journey to

Lappland[1308], undertaken when he was quite a young man, that the women

in the northern countries made use of a brown lichen for dyeing which is

evidently _Parmelia omphalodes_ (Fig. 135). He describes it as a “rich

_Lichenoides_ of a brown stercoraceous colour,” and he has stated that

it grew in such abundance in the Island of Aland, that every stone was

covered, especially near the sea. In the _Plantae tinctoriae_[1309] there

is a record of six other lichens used for dyeing: _Lichen Roccella_,

_L. tartareus_, _L. saxatilis_, _L. juniperinus_, _L. parietinus_ and

_L. candelarius_. The value of _Lichen omphalodes_ was also emphasized

by Lightfoot; the women of Scotland evidently appreciated its dyeing

properties as much as other northern peoples.

A series of memoirs on the utility of lichens written by Willemet[1310],

Amoreux and Hoffmann, and jointly published at Lyons towards the end of

the eighteenth century, represents the views as to the economic value of

lichens held by scientific botanists of that time. All of them cite the

various dye-species, and Hoffmann, as already stated, gives illustrations

of colours that can be obtained. It has been once and again affirmed

that _Parmelia saxatilis_ yields a red colour, but Zopf[1311] denies

this. It contains saxatillic acid which is colourless when extracted but

on boiling gives a clear reddish-yellow to reddish-brown solution which

dyes wool and silk directly without the aid of a mordant. Zopf[1311]

observed the process of dyeing followed in South Tyrol: a layer of the

lichen was placed in a cooking pot, above this a layer of the material

to be dyed, then lichen and again the material until the pot was filled.

It was covered with water and boiled three to four hours, resulting in a

beautiful rust-brown and peculiarly fast dye.

[Illustration: Fig. 135. _Parmelia omphalodes_ Ach. (S. H., _Photo._).]

Reddish- or rust-brown dye is also obtained from _Haematomma ventosum_

and _H. coccineum_, a yellow-brown from _Parmelia conspersa_ (salazinic

acid), and other shades of brown from _Parmelia perlata_, _P. physodes_,

_Lobaria pulmonaria_ and _Cetraria islandica_.

Yellow lichens in general furnish yellow dyes, as for instance _Xanthoria

parietina_ which gives either brown or yellow according to treatment and

_Cetraria juniperina_ which forms a beautiful yellow colouring substance

on boiling. _Teloschistes flavicans_ and _Letharia vulpina_ yield very

similar yellow dyes, and from _Lecanora parella_ (Fig. 39), _Pertusaria

melaleuca_ and _Usnea barbata_ yellow colours have been obtained.

_Candelariella vitellina_ and _Xanthoria lychnea_ both contain yellow

colouring agents and have been employed by the Swedes for dyeing the

candles used in religious ceremonies.

_g._ COLLECTING OF DYE-LICHENS. Lauder Lindsay[1312] made exhaustive

studies of dye-lichens both in the field and in the laboratory, and

recorded results he obtained from the micro-chemical examination of

540 different specimens. He sought to revive and encourage the use of

their beautiful colour products among country people; he has given the

following practical hints to collectors:

1. That crustaceous dwarf pale-coloured species growing on rocks, and

especially on sea-coasts, are most likely to yield red and purple dyes

similar to orchil, cudbear or litmus; while on the other hand the

largest, most handsome foliaceous or fruticose species are least likely.

2. That the colour of the thallus is no indication of colorific power

(in orchil lichens), inasmuch as the red or purple colouring substances

are the result of chemical action on crystalline colorific “principles”

previously devoid of colour.

3. That alterations in physical characters, chemical composition and

consequently in dyeing properties are very liable to be produced by

modification in the following external circumstances:

(i) Degree of moisture.

(ii) Degree of heat.

(iii) Degree of exposure to light and air.

(iv) Climate.

(v) Elevation above the sea.

(vi) Habitat; nature of basis of support.

(vii) Age.

(viii) Seasons and atmospheric vicissitudes, etc.

August has been recommended as the best month for collecting dye-lichens:

_i.e._ just after the season of greatest light and heat when the

accumulation of acids will be at its maximum.

Some of the acids found useful in dyeing occur in the thalli of a large

number of lichens, many of which are too scantily developed to be of

any economic value. Thus salazinic acid which gives the effective

yellow-brown dye in _Parmelia conspersa_ was found by Zopf in 13 species

and varieties. It has since been located by Lettau[1313] in 72 different

lichens, many of them, however, with poorly developed or scanty thalli,

so that no technical use can be made of them.

_h._ LICHEN COLOURS AND SPECTRUM CHARACTERS. In a comparative study of

vegetable colouring substances, Sorby[1314] extracted yellow colouring

matters from various plants distinguished by certain spectrum characters.

He called them the “lichenoxanthine group” because, as he explains,

“these xanthines occur in a more marked manner in lichens than in plants

having true leaves and fronds.” Orange lichenoxanthine he found in

_Peltigera canina_, _Platysma glaucum_, etc., when growing well exposed

to the sun. Lichenoxanthine he obtained from the fungus _Clavaria

fusiformis_; it was difficult to separate from orange lichenoxanthine.

Yet another, which he terms yellow lichenoxanthine, he obtained most

readily from _Physcia_ (_Xanthoria_) _parietina_. The solutions of these

substances vary according to Sorby in giving a slightly different kind of

spectrum. He did not experiment on their dyeing properties.

F. LICHENS IN PERFUMERY

_a._ LICHENS AS PERFUMES. There are a few lichens that find a place in

Gerard’s[1315] _Herball_ and that are praised by him as being serviceable

to man. Among others he writes of a “Moss that partakes of the bark of

which it is engendered. It is to be used in compositions which serve

for sweet perfumes and that take away wearisomeness.” At a much later

date we find Amoreux[1316] recording the fact that _Lichen_ (_Evernia_)

_prunastri_, known as “Mousse de Chêne,” was used as a perfume plant.

Though lichens are not parasitic, the idea that they owed something of

their quality to the substratum was firmly held by the old herbalists.

It appears again and again in the descriptions of medicinal lichens, and

still persists in this matter of perfumes. Hue[1317] states in some notes

to a larger work, that French perfumers extract an excellent perfume from

_Evernia prunastri_ (Fig. 59) known as “Mousse des Chênes” (Oak moss),

and it appears that the plants which grow on oak contain more perfume

than those which live on other trees. The collectors often gather along

with _Evernia prunastri_ other species such as _Ramalina calicaris_ and

_R. fraxinea_, but these possess little if any scent. A still finer

perfume is extracted[1318] from _Lobaria pulmonaria_ called “moss from

the base of the oaks,” but as it is a rarer lichen than _Evernia_ it is

less used. Most of the Stictaceae, to which family _Lobaria_ belongs,

have a somewhat disagreeable odour, but this one forms a remarkable

exception, which can be tested by macerating the thallus and soaking it

in spirit: it will then be found to exhale a pleasant and very persistent

scent. These lichens are not, however, used alone; they are combined with

other substances in the composition of much appreciated perfumes. The

thallus possesses also the power of retaining scent and, for this reason,

lichens frequently form an ingredient of potpourri.

_b._ LICHENS AS HAIR-POWDER. In the days of white-powdered hair, use

was occasionally made of _Ramalina calicaris_ which was ground down and

substituted for the starch that was more commonly employed.

In older books on lichenology constant reference is made to a hair-powder

called “Pulvis Cyprius” or “Cyprus powder” and very celebrated in the

seventeenth century. It was believed to beautify and cleanse the hair by

removing scurf, etc. _Evernia prunastri_ was one of the chief ingredients

of the powder, but it might be replaced by _Physcia ciliaris_ or by

_Usnea_. The virtue of the lichens lay in their capacity to absorb and

retain perfume. The powder was for long manufactured at Montpellier

and was a valuable monopoly. Its composition was kept secret, but

Bauhin[1319] (J.) published an account of the ingredients and how to

mix them. Under the title “Pulvis Cyprius Pretiosius” a more detailed

recipe of the famous powder was given by Zwelser[1320], a Palatine

medical doctor. The lichen employed in his preparation, as in Bauhin’s,

is _Usnea_, but that may include both _Evernia_ and _Physcia_ as they

are all tree plants. He gives elaborate directions as to the cleaning of

the lichen from all impurities—it is to be beaten with a stick, washed

repeatedly with limpid and pure water, placed in a linen cloth and dried

in the sun till it is completely bleached and deprived of all odour and

taste.

When well dried it was placed in a basket in alternate layers with

freshly gathered, entire flowers of roses and jasmine (or flowers of

orange and citrus when possible). The whole was compressed by a heavy

weight, and each day the flowers were renewed until the “Usnea” was

thoroughly impregnated with a very fragrant odour. It was then reduced to

a fine powder and ready for other ingredients. To each pound should be

added:

1-1/2 oz. powdered root of white Iris.

1-1/2 oz. of _Cyperus_ (a sedge).

1 scruple or half drachm of musk reduced to a pulp with fragrant spirit

of roses.

1/2 drachm of ambergris dissolved in a scruple of genuine oil of roses,

or oil of jasmine or oranges as may be preferred.

Zwelser adds:

“This most fragrant royal powder when sprinkled on the head invigorates

by its remarkably pleasant odour; by its astringency and dryness it

removes all impurities, and, since it operates with no viscosity nor

sticks firmly either to skin or hair, it is easily removed from the hair

of the head.”

G. SOME MINOR USES OF LICHENS

The possibility of extracting gum or mucilage from lichens was

demonstrated by the Russian scientist, Professor Georgi[1321], and later

by Amoreux[1322], the method employed being successive boiling of the

plants. The larger foliose or fruticose forms were specially recommended.

At a later date, during the Napoleonic wars, the “ingenious Lord

Dundonald[1323],” of great fame as an inventor, published an account

of the extraction process and of the application of the gum to

calico-printing, staining and manufacture of paper, dressing and

stiffening silks. Lord Dundonald’s aim was to replace the gum Senegal,

then a monopoly of the French, who were in possession of the Settlement

of Senegambia. He took out a patent for his invention, but whether the

gum was successfully used is not recorded.

According to Henneguy[1324], lichen mucilage, as a substitute for gum

arabic, has been used at Lyons with advantage in the fabrication of dyed

materials.

APPENDIX

POSTSCRIPT TO CHAPTER VII[1325]

In a remarkable paper on _The Symbiosis of Lichens_[1326], Dr A.

Henry Church has presented a new and striking view of the origin and

development of lichens: he has sought to link them up with other classes

of vegetation that, in the great transmigration, passed from sea to

land. As we know from his _Thalassiophyta[1327] and the subaerial

transmigration_, he holds that primeval algae of advanced form and

structure were left exposed on dry land by the gradually receding waters,

and those that successfully adapted themselves to the changed conditions

formed the basis of the land flora. A certain number of the algae lost

their surface tissues containing chlorophyll and they had perforce

to secure from other organic sources the necessary carbohydrates:

they adopted a heterotrophic existence as saprophytic or parasitic

fungi. Fungi are a backward race (deteriorated according to Dr Church)

as regards their soma, but in number, distribution and variety of

spore-production, they are eminently successful plants.

Lichens are similarly regarded by Dr Church as derived from stranded

contemporaneous types of marine algae—crustaceous, foliose and

fruticose, that had also lost their chlorophyll, but by taking into

association green algal units of a lower grade they established a

vicarious photosynthesis. But, to quote his own words[1328], “as the

alga-lichen-fungus left the sea, so it remained: it might deteriorate,

but it certainly never advanced, once the sea factors which produced it

were eliminated, it simply stopped along these lines.”

And again[1329]: “Lichens thus present an interesting case of an algal

race deteriorating along the lines of a heterotrophic existence, yet

arrested, as it were, on the somatic down-grade, by the adoption of

intrusive algal units of lower degree to subserve photosynthesis (much

in the manner of the marine worm _Convoluta_). Thus arrested, they have

been enabled to retain more definite expression of more deeply inherent

factors of sea-weed habit and construction than any other race of fungi;

though closely paralleled by such types as _Xylaria_ (Ascomycete)

and _Clavaria_ (Basidiomycete), which have followed the full fungus

progression as holosaprophytic on decaying plant residues.”

Dr Church’s theory is of vivid interest and might be convincing were

there no possibility and no proof of advance within the symbiotic

plant, but in numbers of crustaceous thalli, there is evident,

by normal or abnormal[1330] development, the first advance to

the formation of rudimentary squamules, a condition diagnosed as

subsquamulose. “Deterioration” of the lichen plant—when it occurs owing

to unfavourable conditions—is a reversion to the leprose early stage

of the association; there is no evidence of reversion from fruticose

or foliose to squamulose. A glance at the table of lichen phyla[1331]

shows progression again and again from the crustaceous forms onwards.

In such a phylum as Physciaceae (with colourless polarilocular spores)

there is a clear example of a closely connected series; the different

types of thallus—crustaceous, squamulose, foliose and fruticose—are all

represented and form a natural sequence, being well delimited by the

unusual form of the spore and by the presence of parietin in thallus or

apothecium.

That there has been development seems absolutely certain, and that

along the lines sketched in the chapter on phylogeny. Progress has

been mainly in the thallus, but there has also been change and advance

in the reproductive organs, more especially in the spores which in

several families reach a size and septation unparalleled in fungi.

That association with green algal cells stimulated the fungus to new

development is the view taken of the lichen plant and emphasized in the

present volume. But it seems more in accordance with the polyphyletic

origin and recurring parallel development in the phyla that association

began at the elementary crustaceous stage, and that the lichen soma was

gradually evolved within what is after all a very limited and simple

structure.

ADDENDUM

FOOTNOTE TO PAGE 404

E. M. Holmes[1332] has published recently an account of a substance which

seems in some respects to answer to the description of manna (Exodus

xvi.; Numbers xi.) more nearly than the generally accepted _Lecanora

esculenta_. The information is quoted from Swann’s book: _Fighting the

slave-hunters in Central Africa_. The author writes (p. 116): “I was

shown a curious white substance similar to porridge. It was found early

in the morning before the sun rose. On examination it was found to

possess all the characteristics of the manna ... of the Israelites. In

appearance it resembled coriander seed, was white in colour like hoar

frost, sweet to the taste, melted in the sun and if kept over night was

full of worms in the morning. It required to be baked if you intended to

keep it for any length of time. It looked as if it was deposited on the

ground in the night.” The writer has suggested that “the substance might

be mushroom spawn as, on the spot where it melted tiny fungi sprung up

the next night.” Swann’s statement has been confirmed by Dr Wareham, a

medical missionary from the same district, who states, however, that it

is of rare occurrence.

FOOTNOTES

[1] E. Acton (1909) has described a primitive lichen _Botrydina

vulgaris_, in which there is no fruiting stage, and in which the fungus

seems to show affinity with a Hyphomycete.

[2] Luyken 1809.

[3] Hornschuch 1819.

[4] Raab 1819.

[5] Dillenius 1741, p. 200.

[6] Wallroth 1825.

[7] Agardh 1820.

[8] See p. 27.

[9] Schwendener 1867.

[10] Fink 1913.

[11] Lindsay 1876.

[12] Nylander 1869.

[13] Crombie 1891.

[14] Nylander 1891.

[15] Crombie 1874.

[16] Crombie 1877.

[17] Crombie 1885.

[18] Fink 1913.

[19] Elfving 1913.

[20] Moreau 1918.

[21] Peirce 1898.

[22] French 1898.

[23] Morison 1699.

[24] Tournefort 1694 and 1700.

[25] Dillenius 1741.

[26] Krempelhuber 1867-1872.

[27] _Grete Herball_ 1526.

[28] Ruel 1536.

[29] Dorstenius 1540.

[30] Camerarius 1586.

[31] Tabernaemontanus 1590.

[32] L’Obel 1576.

[33] Dodoens 1583.

[34] Gerard 1597.

[35] Schwenckfeld 1600.

[36] Colonna 1606.

[37] Bauhin 1623, pp. 360-2.

[38] Parkinson 1640.

[39] How 1650.

[40] Merrett 1666.

[41] Plot 1686.

[42] Morison 1699.

[43] Ray 1670.

[44] Ray 1686.

[45] Ray 1690.

[46] Petiver 1695.

[47] Plukenet 1691-1696.

[48] Malpighi 1686.

[49] Porta 1688.

[50] Tournefort 1694.

[51] Tournefort 1700.

[52] Rupp 1718.

[53] Buxbaum 1721.

[54] Vaillant 1727.

[55] Dillenius 1724 and 1741.

[56] Micheli 1729.

[57] Dillenius 1719.

[58] See Druce and Vines 1907.

[59] Crombie 1880.

[60] Haller 1742.

[61] Linnaeus 1753.

[62] Schneider 1897.

[63] Hill 1751. Hill’s genus _Collema_ is _Nostoc_, etc.

[64] Hill 1760.

[65] Watson 1759.

[66] Scopoli 1760.

[67] Adanson 1763.

[68] Hudson 1762 and 1778.

[69] Withering 1776.

[70] Lightfoot 1777.

[71] Dickson 1785.

[72] Weber 1780.

[73] Sibthorp 1794.

[74] Relhan 1785 and 1820.

[75] Smith 1790.

[76] Hoffmann 1798.

[77] Persoon 1794.

[78] Buxbaum 1728.

[79] Petiver 1712.

[80] Sloane 1796 and 1807.

[81] Swartz 1788 and 1791.

[82] Desfontaines 1798-1800.

[83] Georgi 1797.

[84] Willomet, etc. 1787.

[85] Acharius 1798.

[86] Acharius 1803.

[87] Acharius 1810.

[88] Acharius 1814.

[89] Hue 1908.

[90] De Candolle 1805.

[91] Flörke 1815-1819.

[92] Davies 1813.

[93] Forster 1816.

[94] S. F. Gray 1821.

[95] Carrington 1870.

[96] See _List of the Books_, etc. by John Edward Gray, p. 3, 1872.

[97] Hooker 1821.

[98] Hooker 1831.

[99] Greville 1823-1827.

[100] Greville 1824.

[101] Hooker 1833.

[102] Taylor 1836.

[103] Fries 1831.

[104] Fée 1824.

[105] Flörke 1828.

[106] Wallroth 1829.

[107] Delise 1822.

[108] Chevalier 1824.

[109] Wallroth 1825.

[110] Meyer 1825.

[111] Holle 1849.

[112] Koerber 1839.

[113] Michaux 1803.

[114] Mühlenberg 1813.

[115] Torrey 1819.

[116] Halsey 1824.

[117] Tuckerman 1839.

[118] Fée 1824.

[119] Martius 1833.

[120] Montagne 1851.

[121] Hooker 1841.

[122] Schaerer 1850.

[123] Eschweiler 1824.

[124] Fée 1824.

[125] De Notaris 1846.

[126] Massalongo 1852.

[127] Norman 1852.

[128] Koerber 1855.

[129] Mudd 1861.

[130] Lindsay 1856.

[131] Leighton 1851, etc.

[132] See Hue 1899.

[133] Nylander 1854 and 1855.

[134] Tulasne 1852.

[135] Lauder Lindsay 1859.

[136] Itzigsohn 1854-1855.

[137] Speerschneider 1853.

[138] Sachs 1855.

[139] Thwaites 1849.

[140] Schwendener 1863-1868.

[141] Leighton 1851.

[142] Leighton 1854.

[143] Leighton 1856.

[144] Mudd 1865.

[145] Th. Fries 1858.

[146] Schwendener 1867.

[147] Nylander 1874.

[148] Crombie 1885.

[149] Lett 1890.

[150] Fünfstück 1898.

[151] Zahlbruckner 1903-1907.

[152] Ventenat 1794, p. 36.

[153] Cassini 1817, p. 395.

[154] Agardh 1820.

[155] Scopoli 1760, p. 79.

[156] Persoon 1794, p. 17.

[157] Sprengel 1804, p. 325.

[158] Wallroth 1825, I.

[159] Wallroth 1825, I., p. 303.

[160] Fries 1831, pp. lvi and lvii.

[161] Kützing 1843.

[162] Thwaites 1849, pp. 219 and 241.

[163] Flotow 1850.

[164] Sachs 1855.

[165] Itzigsohn 1855.

[166] Itzigsohn 1854.

[167] Hicks 1860 and 1861.

[168] Speerschneider 1853.

[169] Famintzin and Baranetzky 1867.

[170] Baranetzky 1869.

[171] Itzigsohn 1867.

[172] Bayrhoffer 1851.

[173] Tulasne 1852.

[174] Speerschneider 1854.

[175] de Bary 1866, p. 242.

[176] Schwendener 1860, p. 125.

[177] de Bary 1866, p. 291.

[178] Nylander 1870.

[179] Elfving 1903 and 1913.

[180] See p. 133.

[181] Minks 1878 and 1879.

[182] Müller 1878 and 1884.

[183] Zukal 1884.

[184] Darbishire 1895¹.

[185] Schwendener 1860, etc.

[186] Schwendener 1867.

[187] Schwendener 1868, p. 195.

[188] Schwendener 1869.

[189] Rees 1871.

[190] Bornet 1872.

[191] The authors quoted have been followed in their designation

of the various green algae that form lichen gonidia. It is however

now recognized (Wille 1913) that either _Protococcus viridis_ Ag.,

_Chlorella_ or other Protococcaceae may form the universal green coating

on trees, etc., and be incorporated as lichen gonidia. _Pleurococcus

vulgaris_ Naeg. and _Pleurococcus Naegeli_ Chod. are synonyms of

_Protococcus viridis_. In that alga there is no pyrenoid, and no

zoospores are formed.

The genus _Cystococcus_, according to Chodat (1913), is characterized

by the presence of a pyrenoid and by reproduction with zoospores and is

identical with _Pleurococcus vulgaris_ Menegh. (non Naeg.), though Wille

regards Meneghini’s species as of mixed content. Paulson and Hastings

(1920) now find that Chodat’s pyrenoid is the nucleus of the cell.

[192] Woronin 1872.

[193] Archer 1873, 1874, 1875.

[194] Bornet 1873 and 1874.

[195] Treub 1873.

[196] Borzi 1875.

[197] Stahl 1877.

[198] Bonnier 1886 and 1889.

[199] Bonnier was probably experimenting with an _Arthopyrenia_.

_Verrucaria_ species combine with _Protococcus_ or according to Chodat

with _Coccobotrys_ gen. nov.

[200] Nylander 1858.

[201] Fuisting 1868, p. 674.

[202] Winter 1876, p. 264.

[203] Stahl 1877.

[204] See p. 62.

[205] Wainio 1890, 2, p. 29.

[206] Reinke 1872, p. 108.

[207] Reinke 1873¹.

[208] Reinke 1873², p. 98.

[209] Frank 1876.

[210] de Bary 1879.

[211] Bornet 1873.

[212] Hedlund 1892.

[213] Peirce 1899.

[214] Hue 1915.

[215] Lindau 1895¹.

[216] Peirce 1899.

[217] Claassen 1914.

[218] Frank 1876.

[219] Lindau 1895.

[220] Bachmann 1913.

[221] Cunningham 1879.

[222] Ward 1884.

[223] Jennings 1895.

[224] Fitting 1910.

[225] Bornet 1873.

[226] Bonnier 1889².

[227] Schwendener 1867.

[228] Elenkin 1902¹ and 1904¹, 1904².

[229] Elenkin 1906².

[230] Danilov 1910.

[231] Paulson and Hastings 1920.

[232] Nienburg 1917.

[233] Zukal 1891.

[234] Sutherland 1915.

[235] Beyerinck 1890.

[236] Artari 1902.

[237] See p. 56.

[238] Artari 1902.

[239] Treboux 1912.

[240] Chodat 1913.

[241] See Paulson and Hastings 1920.

[242] Keeble 1910.

[243] Reinke 1872.

[244] Dufrenoy 1918.

[245] Artari 1899.

[246] Etard and Bouilhac 1898.

[247] Radais 1900.

[248] Artari 1901.

[249] Chodat 1913.

[250] Treboux 1905.

[251] Marshall Ward 1884.

[252] Uhlir 1915.

[253] Tobler 1911.

[254] Zopf 1907.

[255] Chambers 1912.

[256] Chodat 1913.

[257] See note Paulson and Hastings, p. 28.

[258] Chodat 1913.

[259] Gargeaune 1911.

[260] Servettaz 1913.

[261] See p. 65.

[262] Wettstein 1915.

[263] Meyer 1825.

[264] Holle 1849.

[265] Tulasne 1852.

[266] Bonnier 1889².

[267] Term coined by Lindau (1899) to describe the pseudo-cellular tissue

of lichens and fungi now referred to as “plectenchyma.”

[268] Wainio 1897.

[269] Möller 1887.

[270] Tobler 1909.

[271] Wahrlich 1893.

[272] Baur 1898.

[273] Darbishire 1899.

[274] Kienitz-Gerloff 1902.

[275] Meyer 1902.

[276] Salter 1902.

[277] Nylander (1866) gave the term “gonimia” to the blue-green algae of

the Phycolichens, retaining the term “gonidia” for the bright-green algae

of the Archilichens: the distinction is not now maintained.

[278] For further details see also the chapter on Classification.

[279] See p. 133.

[280] Krempelhuber 1873.

[281] Chodat 1913.

[282] Paulson and Hastings 1920.

[283] Paulson in litt.

[284] Acton 1909.

[285] Bialosuknia 1909.

[286] Hue 1905.

[287] Deckenbach 1893.

[288] In a comparative study of leaf algae from Ceylon and Barbadoes,

N. Thomas (1913) came to the conclusion that Marshall Ward’s alga in

its early stages is the same as _Phyllactidium tropicum_ Moebius; and

that the Barbadoes alga with which she was working represented the older

stages, it being then subcuticular in habit, forming rhizoids, barren and

sterile aerial hairs and subcuticular zoosporangia.

[289] De Toni 1889.

[290] Bornet 1873.

[291] Fünfstück 1899.

[292] Hedlund 1892.

[293] Zukal 1895, p. 19.

[294] Moebius 1888.

[295] Frank 1876, p. 158.

[296] Stahl 1877.

[297] Neubner 1893.

[298] Krabbe 1891.

[299] Forssell 1885.

[300] Hue 1910.

[301] Harmand 1913, p. 1050.

[302] Forssell 1886.

[303] See Chap. VII.

[304] Lindau 1895.

[305] Darbishire 1897.

[306] Nienburg 1917.

[307] Bonnier 1888 and 1889².

[308] Bonnier 1889.

[309] Forssell 1884, p. 34.

[310] Zahlbruckner 1902.

[311] Lindau 1899.

[312] Reinke 1895.

[313] Zukal 1895, p. 562.

[314] Zahlbruckner 1907.

[315] Hue 1899.

[316] Wainio has adopted this term for growing hyphae 1897, p. 33.

[317] Tulasne 1852.

[318] Zukal 1895.

[319] Zukal 1895.

[320] Schwendener 1866.

[321] Schwendener 1863.

[322] Hue 1906.

[323] See p. 83.

[324] Malinowski 1911.

[325] Steiner 1881.

[326] Fünfstück 1899.

[327] Bachmann 1913.

[328] See p. 215.

[329] Friedrich 1906.

[330] Bachmann 1907.

[331] Bachmann 1904.

[332] Bachmann 1904.

[333] Stahlecker 1906.

[334] Lang 1903.

[335] Fünfstück 1899.

[336] Darbishire 1897.

[337] Frank 1876.

[338] Bornet 1873, p. 81.

[339] Lindau 1895.

[340] Bitter 1899.

[341] See p. 83.

[342] Friedrich 1906.

[343] See p. 76.

[344] See p. 126.

[345] Schwendener 1860, 1863 and 1868.

[346] Zukal 1895, p. 1305.

[347] Hue 1906.

[348] Heber Howe 1912.

[349] Hue 1911.

[350] Schwendener 1863, p. 180.

[351] Darbishire 1897.

[352] Rosendahl 1907.

[353] See p. 96.

[354] See p. 133.

[355] Rosendahl 1907.

[356] Meyer 1902.

[357] See p. 52.

[358] Nylander 1858.

[359] Hue 1898.

[360] Rosendahl 1907.

[361] Darbishire 1912.

[362] Porter 1919.

[363] Darbishire 1897.

[364] Schwendener 1860.

[365] Rosendahl 1907.

[366] Meyer 1902.

[367] Reinke 1895, p. 186.

[368] Bitter 1901.

[369] Sernander 1901.

[370] Parfitt in Leighton 1871, p. 470.

[371] Galløe 1915.

[372] Bitter 1899.

[373] Sturgis 1890.

[374] See p. 108.

[375] Darbishire 1898.

[376] Darbishire 1895.

[377] Brandt 1906.

[378] Hue 1906.

[379] Haberlandt 1896.

[380] Schulte 1904.

[381] See p. 120.

[382] Lutz 1894.

[383] Peirce 1898.

[384] Zopf 1903.

[385] Lindau 1895.

[386] Brandt 1906.

[387] Porter 1916.

[388] Darbishire 1898.

[389] Wainio 1880.

[390] Krabbe 1891.

[391] Wainio 1897.

[392] Wainio 1880.

[393] Krabbe 1891.

[394] Krabbe 1891.

[395] Baur 1904.

[396] Wainio 1880.

[397] Chodat 1913.

[398] Wainio 1897.

[399] Baur 1904.

[400] Wainio 1897.

[401] Wainio 1897.

[402] Lindsay 1859, p. 171.

[403] Wainio 1897.

[404] Wainio 1897, p. 9.

[405] Wainio 1880.

[406] Krabbe 1891.

[407] Necker 1871.

[408] Persoon 1794.

[409] Acharius 1803.

[410] Wallroth 1829, p. 61.

[411] Tulasne 1852.

[412] Koerber 1855.

[413] Reinke 1894.

[414] Sättler 1914.

[415] Nienburg 1908.

[416] See p. 183.

[417] Wainio 1897.

[418] Baur 1904.

[419] Wolff 1905.

[420] Aigret 1901.

[421] Wainio 1897.

[422] Wainio 1890, p. 67.

[423] Reinke 1895.

[424] Nylander 1858, p. 63.

[425] Acharius 1810, p. 12.

[426] Haller 1768, p. 85.

[427] Schreber 1791, p. 768.

[428] Meyer 1825, p. 148.

[429] Delise 1822.

[430] Nylander 1858, p. 14.

[431] Nylander 1860, p. 333.

[432] Schwendener 1863, p. 169.

[433] Wainio 1890, I. p. 183.

[434] Schwendener 1863, p. 169.

[435] Stizenberger 1895.

[436] Zukal 1895, p. 1355.

[437] Wainio 1909.

[438] Schwendener 1863, p. 169.

[439] Jatta 1889, p. 48.

[440] Zukal 1895, p. 1357.

[441] Rosendahl 1907.

[442] Zukal 1895.

[443] Reinke 1895, p. 183.

[444] Darbishire 1901.

[445] Brandt 1906.

[446] Bitter 1899.

[447] Nylander 1874².

[448] Bitter 1901².

[449] Zukal 1895, p. 1348.

[450] Acharius 1803.

[451] Hue 1904 and 1910.

[452] Flörke 1815, IV. p. 15.

[453] Wallroth 1825, p. 678.

[454] Th. M. Fries 1858.

[455] Forssell 1884.

[456] Leighton 1869.

[457] Nylander 1878.

[458] Schneider 1897.

[459] Hue 1910.

[460] Hue 1910.

[461] Tuckerman 1875.

[462] Schneider 1897, p. 58.

[463] Nylander 1869.

[464] Bornet 1873, p. 72.

[465] Forssell 1885, p. 24.

[466] Riddle 1910.

[467] Babikoff 1878.

[468] Th. M. Fries 1866.

[469] Winter 1877.

[470] Schneider 1897.

[471] Etard and Bouilhac 1898.

[472] Hue 1910.

[473] Sernander 1907.

[474] Bitter 1904.

[475] Bitter 1904.

[476] Linkola 1913.

[477] Acharius, 1798, p. xix, and 1810, pp. 8 and 10.

[478] Malpighi, 1686, p. 50, pl. 27, fig. 106.

[479] Micheli 1729, pp. 73, 74.

[480] Linnaeus 1737, p. 325.

[481] Hedwig 1798.

[482] Sprengel 1807, Letter XXIII.

[483] Wallroth 1825, I. p. 595.

[484] Koerber 1841.

[485] Schwendener 1860.

[486] Meyer 1825, p. 170.

[487] Krabbe 1891.

[488] Bitter 1901.

[489] Schwendener 1860, p. 137.

[490] Wainio 1897, p. 32.

[491] Reinke 1895, p. 380.

[492] Bitter 1901.

[493] Lesdain 1910.

[494] Schwendener 1860.

[495] Nilson 1903.

[496] Darbishire 1897.

[497] Bitter 1901, p. 191.

[498] Krabbe 1891.

[499] Darbishire 1907.

[500] Tobler 1911², 11.

[501] Bitter 1901².

[502] Lindau 1895.

[503] Nilson 1903.

[504] Bitter 1904.

[505] Acharius 1798, pp. 2, 87.

[506] Fries 1825.

[507] Hooker 1833.

[508] Taylor 1836.

[509] Rosendahl 1907.

[510] Bitter 1899.

[511] Nilson 1903.

[512] Kajanus (Nilson) 1911.

[513] Zopf 1903.

[514] Zopf 1905².

[515] Bitter 1899.

[516] Swartz 1788.

[517] Gmelin 1791.

[518] Woodward 1797.

[519] Fries 1825.

[520] Nylander 1855.

[521] Mattirolo 1881.

[522] Johow 1884.

[523] Wainio 1890.

[524] Möller 1893.

[525] Malpighi 1686.

[526] Tournefort 1694.

[527] Morison 1699.

[528] Micheli 1729.

[529] Micheli, Pls. 52 and 56.

[530] Dillenius 1741.

[531] Linnaeus 1737.

[532] Necker 1771, p. 257.

[533] Scopoli 1772.

[534] Koelreuter 1777.

[535] Hoffmann 1784.

[536] Hedwig 1784.

[537] Acharius 1810.

[538] Hornschuch 1821.

[539] Wallroth 1825.

[540] Meyer 1825.

[541] Sprengel 1804.

[542] Luyken 1809.

[543] Persoon 1801.

[544] See also p. 166.

[545] Wainio 1890.

[546] Tulasne 1852.

[547] Fuisting 1868.

[548] Stahl 1877.

[549] Borzi 1878.

[550] Baur 1898.

[551] Fünfstück (1902) suggests that the lichen worked at by Baur is

_Collema cheileum_ Ach.

[552] Krabbe 1883.

[553] Mäule 1891.

[554] F. Bachmann 1912.

[555] This species of _Collema_ has been described as _Collemodes

Bachmannianum_ by Bruce Fink 1918.

[556] F. Bachmann 1913.

[557] Wainio I. 1890.

[558] Wolff 1905.

[559] Stahl 1877.

[560] Forssell 1885².

[561] Zukal 1887, p. 42.

[562] Borzi 1878.

[563] Lindau 1888.

[564] Mäule 1891.

[565] Darbishire 1900.

[566] Baur 1904.

[567] Lindau 1888.

[568] Darbishire 1900.

[569] See also p. 180.

[570] Nienburg 1908.

[571] Wainio I. 1890.

[572] Darbishire 1900.

[573] Baur 1901.

[574] Baur 1904.

[575] Nienburg 1908.

[576] Harper 1900.

[577] Guilliermond 1904, p. 60.

[578] Baur 1899.

[579] Sturgis 1890.

[580] Nienburg 1908.

[581] Schwendener 1864.

[582] Wahlberg 1902.

[583] Baur 1904.

[584] Brown 1911.

[585] Moreau 1916.

[586] Lindau 1888.

[587] Fünfstück 1884.

[588] Baur 1904.

[589] Nienburg 1908.

[590] Rosendahl 1907.

[591] Lindau 1888.

[592] Baur 1904.

[593] Wolff 1905.

[594] Fünfstück 1902.

[595] Krabbe 1882.

[596] Baur 1901.

[597] Fünfstück 1902.

[598] Darbishire 1897.

[599] See also p. 147.

[600] Wolff 1905.

[601] See Chap. VII.

[602] Krabbe 1883 and 1891.

[603] Baur 1904.

[604] Sättler 1914.

[605] See Chap. VII.

[606] Fuisting 1868.

[607] Stahl 1877.

[608] Baur 1904.

[609] Baur 1901.

[610] Krabbe 1882.

[611] Forssell 1883.

[612] Wainio 1890, p. x.

[613] Neubner 1893.

[614] Fünfstück 1884.

[615] Darbishire 1913.

[616] Moreau 1915.

[617] Sturgis 1890.

[618] Metzger 1903.

[619] Baur 1904.

[620] Moreau 1916.

[621] Krabbe 1882.

[622] Lindau 1899.

[623] Wolff 1905.

[624] Rosendahl 1907.

[625] Bitter 1901².

[626] Baur 1904.

[627] Nienburg 1908.

[628] Krabbe 1882.

[629] Schulte 1904.

[630] Wainio 1890.

[631] Schikorra 1909.

[632] Harper 1900.

[633] Fraser 1907.

[634] Thaxter 1912.

[635] Faull 1911.

[636] Dawson 1900.

[637] Brooks 1910.

[638] Blackman and Welsford 1912.

[639] Lindau 1899.

[640] Van Tieghem 1891.

[641] Zukal 1895.

[642] Wainio 1890.

[643] Steiner 1901.

[644] See also Chap. VII.

[645] F. Bachmann 1913.

[646] Cutting 1909.

[647] Darbishire 1900.

[648] Baur 1904.

[649] See p. 161.

[650] Stahl 1877.

[651] Baur 1898.

[652] F. Bachmann 1912 and 1913.

[653] Darbishire 1900.

[654] Fitzpatrick 1918.

[655] Harper 1900.

[656] Fünfstück 1902.

[657] Schwendener 1864.

[658] Hue 1906.

[659] Lindau 1899.

[660] Hedwig 1784.

[661] Acharius 1803.

[662] Sprengel 1807.

[663] Luyken 1809.

[664] Eschweiler 1824.

[665] Fée 1824.

[666] Mohl 1833.

[667] Dangeard 1894.

[668] Baur 1904.

[669] Nienburg 1908.

[670] Maire 1903.

[671] Bachmann 1913.

[672] Mohl 1833.

[673] Zukal 1895.

[674] Fée 1824.

[675] Meyer 1825.

[676] Holle 1849.

[677] Tulasne 1852.

[678] De Bary 1866-1867.

[679] Haberlandt 1887.

[680] Zopf 1905.

[681] Massalongo 1852.

[682] Koerber 1855.

[683] Wainio 1. 1890, p. 113.

[684] Harper 1899.

[685] Hue 1911².

[686] Tulasne 1852.

[687] Bornet 1873.

[688] Bonnier 1889².

[689] Maire 1905.

[690] Neubner 1893.

[691] Brefeld 1889.

[692] See p. 143.

[693] Bornet 1873.

[694] Bornet’s observations have not been repeated, and it is possible

that he may have been dealing with a parasitic hyphomycetous fungus.

[695] Steiner 1901.

[696] Müller 1881.

[697] Wainio 1890, II. p. 27.

[698] Fée 1873.

[699] Müller 1890.

[700] Tulasne 1851.

[701] Dillenius 1741.

[702] Hedwig 1784 and 1789.

[703] Acharius 1810.

[704] Fries 1831.

[705] Wallroth 1825.

[706] Schaerer 1823-1842.

[707] Flotow 1850.

[708] Itzigsohn 1850.

[709] Tulasne 1851.

[710] Tulasne 1852.

[711] Lindsay 1859 and 1872.

[712] Forssell 1885.

[713] Nienburg 1908.

[714] Möller 1887.

[715] Sturgis 1890.

[716] Nylander 1858, pp. 34, 35.

[717] Nylander, Crombie and others apply the term “sterigma” to the whole

spermatiophore. In the more usual restricted sense, it refers only to the

short process from which the spermatium is abstricted.

[718] Glück 1899.

[719] Steiner 1901.

[720] Gibelli 1866.

[721] Tulasne 1852.

[722] Nylander 1858.

[723] Corda 1839.

[724] Allescher 1901-3.

[725] Keiszler 1911.

[726] Nylander 1858, p. 37.

[727] Möller 1887.

[728] Istvanffi 1895.

[729] Möller 1888.

[730] Hedlund 1892.

[731] Tulasne 1852.

[732] Müller 1885.

[733] Lindsay 1859 and 1872.

[734] Laubert 1911.

[735] Blackman 1904.

[736] Istvanffi 1895.

[737] Plowright 1889.

[738] Sappin-Trouffy 1896.

[739] Brefeld 1891.

[740] De Bary 1866, p. 7.

[741] Gilson 1893.

[742] Winterstein 1893.

[743] Gilson 1894.

[744] The chemical formula of chitin is given as C₆₀H₁₀₀N₈O₃₈, that of

chitosan as C₁₄H₂₆N₂O₁₀.

[745] Escombe 1896.

[746] Wisselingh 1898.

[747] Wester 1909.

[748] Berzelius 1813.

[749] Guérin-Varry 1834.

[750] Mulder 1838.

[751] Berg 1873.

[752] Beilstein ex Errera 1882, p. 16 (note).

[753] Escombe 1896.

[754] Wiesner 1900.

[755] Lacour 1880.

[756] Wisselingh 1898.

[757] Stüde 1864.

[758] Czapek 1905, I. p. 515.

[759] Ulander 1905.

[760] Müller 1905.

[761] Stüde 1864.

[762] Wisselingh 1898.

[763] Schellenberg 1896.

[764] Escombe 1896.

[765] Wester 1909.

[766] Czapek 1905, I. p. 515.

[767] Moreau 1916.

[768] Errera 1882.

[769] Schwendener 1862, p. 231.

[770] De Bary 1866-1867, p. 211.

[771] Gautier 1899.

[772] Herissey 1898.

[773] Czapek 1905, II. p. 257.

[774] Ronceray 1904.

[775] Zopf in Schenk 1890, p. 448.

[776] Knop 1872.

[777] Zopf 1907.

[778] Hamlet and Plowright 1877.

[779] Braconnot 1825.

[780] Zopf 1907.

[781] Errera 1893.

[782] Euler 1908, p. 7.

[783] Rosendahl 1907.

[784] Knop 1872.

[785] Kratzmann 1913.

[786] Zukal 1895, p. 1311.

[787] Kerner and Oliver 1894, p. 235.

[788] Steiner 1881.

[789] Zukal 1884.

[790] Zukal 1886.

[791] Hulth 1891.

[792] Bachmann 1892.

[793] Fünfstück 1895.

[794] Fünfstück 1899.

[795] Bachmann 1904¹.

[796] Lang 1906.

[797] Lang 1906, p. 171.

[798] Bachmann 1892.

[799] Bachmann 1904¹.

[800] Bachmann 1904².

[801] Fünfstück 1895.

[802] Zukal 1895, p. 1372.

[803] Rosendahl 1907.

[804] Zukal 1895.

[805] Fünfstück 1896.

[806] Fünfstück 1899.

[807] Lang 1906.

[808] Beijerinck 1904.

[809] Wehmer 1891.

[810] Stahel 1911.

[811] See p. 218.

[812] Pfeffer 1877.

[813] Pfaff 1826.

[814] Herberger 1830.

[815] Knop and Schnederman 1846.

[816] Hesse 1904.

[817] Zopf 1907, p. 179.

[818] Zopf 1907.

[819] Senft 1907.

[820] Tobler 1909.

[821] Keegan 1907.

[822] Schwarz 1880, p. 264.

[823] Schwendener 1863, p. 180.

[824] Fünfstück 1902.

[825] Heber Howe 1913.

[826] Knowles 1913.

[827] West, W. 1905.

[828] Lettau 1914.

[829] Lettau 1914.

[830] Parietin differs chemically from chrysophanic acid of _Rheum_, etc.

[831] Stenhouse and Groves 1877.

[832] Volkard 1894.

[833] Nylander 1866.

[834] Jumelle 1892.

[835] Sievers 1908.

[836] Zukal 1895.

[837] Beckmann 1907.

[838] Herre 1911².

[839] Sievers 1908.

[840] Jumelle 1892.

[841] Schrenk 1898.

[842] Bonnier 1889².

[843] West 1905.

[844] Sandstede 1904.

[845] Friedrich 1906.

[846] Lindau 1895².

[847] See p. 109.

[848] Uloth 1861.

[849] Zopf 1903.

[850] Zopf 1907.

[851] Ohlert 1871.

[852] See p. 75.

[853] Uloth 1861.

[854] Egeling 1881.

[855] Buchet 1890.

[856] Bachmann 1904.

[857] Bachmann 1911.

[858] Lang 1903.

[859] Stahlecker 1906.

[860] Bitter 1899.

[861] Zukal 1879.

[862] Kihlman 1890.

[863] Jumelle 1892.

[864] Zopf 1890, p. 489.

[865] Jumelle 1892.

[866] Weir 1919.

[867] Wainio 1897, p. 16.

[868] Nienburg 1908.

[869] Metzger 1903.

[870] Bitter 1899.

[871] Wiesner 1895.

[872] Bitter 1901, p. 465.

[873] Fink 1909.

[874] Galløe 1908.

[875] Zukal 1896.

[876] Bitter 1901.

[877] Maheu 1906.

[878] Wiesner 1895.

[879] R. Paulson, ined.

[880] Krempelhuber 1861.

[881] Zukal 1896, p. 111.

[882] Zukal 1896.

[883] Hedlund 1892, p. 22.

[884] Zopf 1893.

[885] Zopf 1907.

[886] Zopf 1892.

[887] Knop 1872.

[888] Bachmann 1890.

[889] A similar reaction with nitric acid is produced on the blue

hypothalline hyphae of _Placynthium nigrum_.

[890] Knowles 1915.

[891] Rosendahl 1907.

[892] John 1819.

[893] Grimbel 1856.

[894] Molisch 1892.

[895] Nilson 1907.

[896] Meyer 1825, p. 44.

[897] Lindsay 1856.

[898] Berkeley 1857.

[899] Weddell 1869.

[900] Phillips 1878.

[901] Scott Elliot 1907.

[902] Vallot 1896.

[903] Bitter 1901.

[904] Heere 1904.

[905] Krabbe 1891, p. 131.

[906] Reinke 1894, p. 18.

[907] Bonnier, see p. 29.

[908] Darbishire, see p. 148.

[909] Tobler, see p. 148.

[910] Stahl 1877, p. 34.

[911] Paulson 1918.

[912] Paulson and Thompson 1913.

[913] Fink 1917.

[914] Baur 1901.

[915] Miyoshi 1901.

[916] Darbishire 1897, p. 657.

[917] Beckmann 1907.

[918] Bitter 1899.

[919] Peirce 1898.

[920] Schrenk 1898.

[921] Elenkin 1901.

[922] See Chap. X.

[923] Mereschkovsky 1918.

[924] Meyer 1825, p. 44.

[925] Paulson and Somerville Hastings 1914.

[926] Crombie 1872.

[927] See p. 35.

[928] Dufrenoy 1918.

[929] Arnold 1874.

[930] Kupfer 1894.

[931] See p. 236.

[932] Malme 1895.

[933] Bitter 1899.

[934] Hofmann 1906.

[935] Almquist 1880.

[936] Bitter 1899.

[937] See p. 237.

[938] Arnold 1874.

[939] Nylander 1852.

[940] Hue 1915.

[941] Th. Fries 1874, p. 343.

[942] Tobler 1911².

[943] Lindsay 1869².

[944] Winter 1877.

[945] _Abrothallus_ has been included in the lichen genus _Buellia_.

[946] Tulasne 1852.

[947] Lindsay 1856.

[948] Crombie 1894.

[949] Kotte 1910.

[950] Zopf 1896.

[951] Zopf 1898, p. 249.

[952] Tobler 1911².

[953] See p. 276.

[954] Elenkin 1901².

[955] Stahl 1904.

[956] Lindsay 1859, 1869, 1871.

[957] Zopf 1896.

[958] Zopf 1898.

[959] Moreau 1916³.

[960] Vouaux 1912, etc.

[961] Bitter 1904.

[962] Zukal 1893.

[963] Lister 1911.

[964] Zopf 1897.

[965] Zukal 1896, p. 258.

[966] Zukal 1896, p. 255.

[967] Cunningham 1879.

[968] Friedrich 1906, p. 401.

[969] See p. 78.

[970] Gleditsch 1775, p. 31.

[971] Lindau 1895, p. 53.

[972] Dufrenoy 1881.

[973] Porter 1917.

[974] Friedrich 1906.

[975] Waite 1893.

[976] Lesdain 1912.

[977] Zopf 1907.

[978] Lesdain 1910.

[979] Zukal 1896, p. 258.

[980] See p. 51.

[981] See p. 177 _et seq._

[982] Zahlbruckner 1903.

[983] Steiner 1896.

[984] Müller-Argau 1880.

[985] Wainio 1890, p. xxiii.

[986] Lloyd 1917.

[987] Rehm 1890.

[988] Reinke 1894.

[989] See p. 260.

[990] Wainio 1890.

[991] Müller-Argau 1862.

[992] Rehm 1890.

[993] Rehm 1890.

[994] Tobler 1911², p. 407.

[995] Lightfoot 1777, p. 965.

[996] See Chap. III.

[997] Forssell 1885.

[998] Hue 1911¹.

[999] See p. 133.

[1000] Zahlbruckner 1907.

[1001] Reinke 1895.

[1002] See p. 126.

[1003] Reinke 1895.

[1004] Neubner 1893.

[1005] Reinke 1895, p. 110.

[1006] Wainio 1890.

[1007] See Chap. III.

[1008] Wainio 1897.

[1009] See Chap. III.

[1010] Sättler 1914.

[1011] See p. 90.

[1012] Darbishire 1912.

[1013] See p. 101.

[1014] See p. 188.

[1015] Dr Church (1920) has published a new conception of the origin of

lichens. See postscript at the end of the volume, p. 421.

[1016] Tournefort 1694.

[1017] Morison 1699.

[1018] Dillenius 1741.

[1019] Linnaeus 1753.

[1020] Acharius 1803.

[1021] Acharius 1810.

[1022] Acharius 1814.

[1023] Wallroth 1825.

[1024] Meyer 1825.

[1025] Nylander 1854.

[1026] Reinke 1894, ’95, ’96.

[1027] Darbishire and Fischer-Benzon 1901.

[1028] Wainio 1887, ’94, ’97.

[1029] Wainio 1890.

[1030] Zahlbruckner 1907.

[1031] Massee 1887.

[1032] Fischer 1890.

[1033] Linnaeus 1753.

[1034] Steiner 1901.

[1035] See p. 56.

[1036] Norman 1872 and ’74.

[1037] Genera marked with an asterisk have not been found in the British

Isles.

[1038] Zukal 1890.

[1039] Hue 1914.

[1040] Hue 1909.

[1041] Hue 1905.

[1042] Zahlbr., in _Hedwigia_, LIX. p. 301, 1917.

[1043] Riddle 1917.

[1044] Bioret 1914.

[1045] Reinke 1895.

[1046] Darbishire 1898.

[1047] Hue 1909.

[1048] Nylander 1855.

[1049] Nylander 1883.

[1050] Lorrain Smith 1906.

[1051] _Neophyllis_ Wils. is synonymous with _Gymnoderma_.

[1052] Lindau 1899.

[1053] Stirton 1877, p. 164.

[1054] A. Zahlbruckner, in _Oesterr. bot. Zeitschr._ 1919, p. 163.

[1055] Bitter 1904².

[1056] Hue 1892.

[1057] Hue 1914.

[1058] Tuckerman 1872, p. 107.

[1059] See p. 188.

[1060] Hue 1908.

[1061] See p. 152.

[1062] Olivier 1907.

[1063] Th. Fries 1867.

[1064] Darbishire 1909.

[1065] Hue 1892.

[1066] Arnold 1890.

[1067] These genera are associated with _Trentepohlia_ algae which are

numerous and abundant in tropical climates, and their presence there may

possibly account for these particular lichens.

[1068] Wainio 1897.

[1069] Wainio 1909.

[1070] Elenkin 1906.

[1071] Darbishire 1905.

[1072] Hue 1915.

[1073] Darbishire 1912.

[1074] Lindsay 1870.

[1075] Calkins 1896.

[1076] Hue 1898.

[1077] Fink 1903.

[1078] Wainio 1896.

[1079] Comm. Heber Howe.

[1080] Herre 1910.

[1081] Nylander 1890.

[1082] Müller 1879.

[1083] Nylander and Crombie 1884.

[1084] Babington 1855.

[1085] Stirton 1875.

[1086] Nylander 1888.

[1087] Hellbom 1896.

[1088] Wilson 1892.

[1089] Müller-Argau 1884.

[1090] Stizenberger 1888-1895.

[1091] Steiner 1895.

[1092] Flagey 1892.

[1093] Wainio 1890.

[1094] Wainio 1890, II. p. 27 (recorded under _Lecidea_).

[1095] Elenkin and Woronichin 1908.

[1096] Jaczewski 1904.

[1097] Steiner 1919.

[1098] Müller 1892.

[1099] Nylander 1867.

[1100] Leighton 1869.

[1101] Nylander 1900.

[1102] Nylander 1891.

[1103] Schimper 1869, p. 145.

[1104] Lindsay 1879.

[1105] Braun 1840.

[1106] Muenster 1846, p. 26.

[1107] Eltingshausen and Debey 1857.

[1108] Engelhardt 1870 (Pl. I. figs. 1 and 2).

[1109] Goeppert 1845, p. 195.

[1110] See Schimper 1869, pp. 145, etc.

[1111] Goeppert and Menge 1883, t. 1, fig. 3.

[1112] Ludwig 1859, p. 61 (t. 9, figs. 1-4), 1859-61.

[1113] Schimper in Zittel 1890.

[1114] Goeppert and Menge 1883.

[1115] Sernander 1918.

[1116] See p. 392.

[1117] Moss 1913.

[1118] Macmillan 1894.

[1119] See p. 240 _et seq._

[1120] See p. 238.

[1121] West 1915.

[1122] Fink 1894.

[1123] Kihlman 1890.

[1124] Nilson 1907.

[1125] Lindsay 1869.

[1126] Sättler 1914.

[1127] Peirce 1898.

[1128] Schrenk 1898.

[1129] Nylander 1866.

[1130] Hue 1898.

[1131] Wheldon and Wilson 1915.

[1132] Paulson and Thompson 1911.

[1133] Paulson and Thompson 1912.

[1134] Chodat 1912.

[1135] Fée 1824.

[1136] Fries 1831.

[1137] Krempelhuber 1861.

[1138] Arnold 1891, etc.

[1139] Fink 1902.

[1140] Watson 1909.

[1141] Paulson 1919.

[1142] Lesdain 1912.

[1143] Fink 1896, etc.

[1144] Stahl 1877.

[1145] Fink 1902, etc.

[1146] Arnold 1891.

[1147] Mayfield 1916.

[1148] Paulson and Thompson 1913.

[1149] Lesdain 1910².

[1150] Lettau 1911.

[1151] Fink 1903.

[1152] Wheldon and Wilson 1907.

[1153] Arnold 1892, p. 34.

[1154] Wheldon and Wilson 1915.

[1155] See p. 358.

[1156] Aigret 1901.

[1157] Kieffer 1894.

[1158] Stahlecker 1906.

[1159] Link 1795.

[1160] Malinowski 1911.

[1161] See also p. 254.

[1162] Fink 1904.

[1163] Link 1789.

[1164] Watson 1918².

[1165] Wheldon and Wilson 1907.

[1166] Flagey 1901.

[1167] Bruce Fink 1902².

[1168] Forssell 1885.

[1169] Servit 1910.

[1170] Malinowski 1911.

[1171] Bachmann 1914.

[1172] West 1912.

[1173] Wheldon and Wilson 1913.

[1174] Stahlecker 1906.

[1175] Malinowski 1911.

[1176] Wheldon and Wilson 1915.

[1177] Wheldon and Wilson 1907.

[1178] Schade 1916.

[1179] Lesdain 1910.

[1180] Arnold 1858.

[1181] Richard 1877.

[1182] Darbishire 1909.

[1183] Cf. p. 234.

[1184] Paulson and Thompson 1913.

[1185] Wheldon and Wilson 1913.

[1186] Weddell 1875.

[1187] Knowles 1913.

[1188] The two morphologically similar plants _Ramalina cuspidata_ and

_R. scopulorum_ are here united under the older name _R. siliquosa_. The

distinction between the two is based on reaction tests with potash, which

give very uncertain results.

[1189] Nylander 1861.

[1190] Knowles 1915.

[1191] Wheldon and Wilson 1913.

[1192] Sandstede 1904.

[1193] Aigret 1901.

[1194] Wheldon and Wilson 1915.

[1195] Watson 1918¹.

[1196] Sandstede 1904.

[1197] McLean 1915.

[1198] Wheldon and Wilson 1915.

[1199] Wheldon and Wilson 1914.

[1200] Maheu 1887.

[1201] Leighton 1867.

[1202] Kihlman 1890.

[1203] Nilson 1907.

[1204] Darbishire 1909.

[1205] Flagey 1901.

[1206] Patouillard 1897.

[1207] Steiner 1895.

[1208] Bruce Fink 1909.

[1209] Herre 1911².

[1210] See p. 97.

[1211] Lindsay 1856.

[1212] Macmillan 1894.

[1213] Knowles _in litt._

[1214] Bruce Fink 1903.

[1215] Lettau 1911.

[1216] Wheldon and Wilson 1915.

[1217] Wheldon and Wilson 1913.

[1218] Linnaeus 1762.

[1219] Guembel 1856.

[1220] Goeppert 1860.

[1221] Salter 1856.

[1222] Bachmann 1911.

[1223] Bachmann 1913.

[1224] Braun 1917.

[1225] Treub 1888.

[1226] Brez 1791.

[1227] Persoon 1794.

[1228] Zukal 1895, p. 1317 (note).

[1229] Zukal 1895, p. 1315.

[1230] Zopf 1896.

[1231] Stahl 1904.

[1232] Hue 1915.

[1233] Zopf 1907.

[1234] Bitter 1899.

[1235] Petch 1913.

[1236] Paulson and Thompson 1913.

[1237] Michael 1884.

[1238] Zopf 1907.

[1239] Lesdain 1910.

[1240] Wheldon 1914.

[1241] See also p. 267.

[1242] Paulson and Thompson 1913.

[1243] Stone 1896.

[1244] Tutt 1900, p. 107.

[1245] Zopf 1907, p. 372.

[1246] Kihlman 1890.

[1247] Linnaeus 1762.

[1248] Johnson 1861.

[1249] Lindsay 1856.

[1250] Willemet 1787.

[1251] Keller 1866.

[1252] Proust 1906.

[1253] Johnson 1861.

[1254] Church 1880.

[1255] Brown 1898.

[1256] Hutchinson 1916.

[1257] Forskål 1875, p. 193.

[1258] Watt 1890.

[1259] Calkins 1892.

[1260] Miyoshi 1893.

[1261] See p. 422.

[1262] Eversmann 1825.

[1263] Berkeley 1849.

[1264] Visiani 1867.

[1265] Errera 1893.

[1266] Müller-Argau 1881, p. 526.

[1267] See p. 138.

[1268] From an examination of old figures of the _Muscus cranii_, Arnold

(1892, p. 53) has decided that several kinds of lichens or hepatics are

included in this designation.

[1269] Parkinson 1640, p. 1313.

[1270] Ray 1686, p. 117.

[1271] Amoreux 1787, p. 46.

[1272] Dillenius 1741, p. 202.

[1273] Lightfoot 1777, II. p. 846.

[1274] Dorstenius 1540.

[1275] Culpepper 1652.

[1276] Hill 1751.

[1277] Cordus 1561.

[1278] Sibbald 1684.

[1279] Ray 1686.

[1280] Linnaeus 1737.

[1281] Scopoli 1760.

[1282] Cramer 1880.

[1283] Kobert 1895.

[1284] Keegan 1905.

[1285] Henneguy 1883.

[1286] Kobert 1895.

[1287] Neubert 1893.

[1288] See p. 228.

[1289] Gmelin 1752, p. 425.

[1290] Léorier 1825.

[1291] Stenberg 1868.

[1292] Richard 1877.

[1293] Henneguy 1883.

[1294] Wainio 1887, p. 47.

[1295] Hellbom 1886, p. 72.

[1296] Hoffmann 1787.

[1297] Westring 1792 and 1793.

[1298] Westring 1805-1809.

[1299] Zopf 1907.

[1300] Ronceray 1904.

[1301] Zopf 1907.

[1302] Zahlbruckner (1905, p. 109) quotes from Czapek a statement that

orchil fermentation is brought about by an obligate aerobic bacillus.

[1303] Zopf 1907, p. 393.

[1304] Lindsay 1855.

[1305] Bohler 1835, N. 10.

[1306] Johnson 1861.

[1307] Lindsay 1855.

[1308] Linnaeus 1711.

[1309] Linnaeus 1760.

[1310] Willemet etc. 1787.

[1311] Zopf 1907.

[1312] Lindsay 1855.

[1313] Lettau 1914.

[1314] Sorby 1873.

[1315] Gerard 1597.

[1316] Amoreux 1787.

[1317] Hue 1889.

[1318] Hue 1900.

[1319] Bauhin 1650, p. 88.

[1320] Zwelser 1672.

[1321] Georgi 1779.

[1322] Amoreux 1787.

[1323] Dundonald 1801.

[1324] Henneguy 1883.

[1325] See p. 302.

[1326] _Journ. Bot._ LVIII. pp. 213-9; 262-7, 1920.

[1327] _Bot. Memoirs_, 3, Oxford, 1919.

[1328] Church _in litt._

[1329] _Journ. Bot._ _l.c._

[1330] See p. 271 _ante_.

[1331] See p. 302 _ante_.

[1332] _Chemist and Druggist_, XCII. pp. 25-26, 1920; _Bot. Abstracts_,

N. 903, p. 135, 1920.

BIBLIOGRAPHY OF BOOKS AND PAPERS CITED IN THE TEXT

=Acharius, Erik.= Lichenographiae Suecicae Prodromus. Linköping, 1798.

—— Methodus Lichenes. Stockholm, 1803.

—— Lichenographia Universalis. Göttingen, 1810.

—— Synopsis Methodica Lichenum. Lund, 1814.

=Acton, E.= Botrydina vulgaris Bréb., a Primitive Lichen. Ann. Bot.

XXIII. pp. 579-587, 1909.

=Adanson, M.= Famille des Plantes. Paris, 1763.

=Agardh, C. A.= Dissertatio de Metamorphosi Algarum. Lund, 1820.

=Aigret, Clém.= Monographie des Cladonia de Belgique. Bull. Soc. Roy.

Bot. Belgique, XL. pp. 43-213, 1901.

=Allescher, Andreas.= Rabenhorst Krypt. Flora, I. 7. Leipzig, 1901-3.

=Almquist, S.= Monographia Arthoniarum Scandinaviae. K. Svensk.

Vet.-Akad. Handl. XVII. No. 6, 69 pp., 1880.

=Amoreux, D. M.= Recherches et expériences sur les divers Lichens. Lyon,

1787.

=Arcangeli, G.= Sulla Questione dei Gonidi. Nuovo Giorn. Bot. Ital. VII.

p. 270, 1875.

=Archer, W.= A Résumé of Recent Views respecting the Nature of Lichens.

Quart. Journ. Microsc. Sci. XIII. pp. 217-235 (2 pls.), 1873.

—— A Further Résumé of Recent Observations on the “Gonidia-Question.” Op.

cit. XIV. pp. 115-139, 1874.

—— On apothecia occurring in some Scytonematous and Sirosiphonaceous

Algae, in addition to those previously known. Op. cit. XV. p. 27 (1 pl.),

1875.

=Arnaud, G.= Sur la Cytologie du Capnodium meridionale et du mycelium des

Fumagines. Comptes Rendus CLV. pp. 726-728 (figs.), 1912.

=Arnold, F.= Lichenologische Fragmente XVI. Flora, LVII. pp. 81-89, etc.,

etc., 1874.

—— Die Lichenen des Fränkischen Juras. Flora, XLI. etc., pp. 81, etc.,

1858-1885. Separate publication, Regensburg, 323 pp., 1885.

—— Die Lichenen des Fränkischen Jura. Denkschr. R. Bayer. Bot. Ges.

Regensburg, VI. pp. 1-61, 1890.

—— Zur Lichenenflora von München (Issued with the Ber. Bayer. Bot. Ges.

München), Abth. I. 147 pp., 1891; II. 76 pp., 1892; III. 45 pp., 1897;

IV. 82 pp., 1898; V. 100 pp., 1900; VI. 24 pp., 1901.

=Artari, A.= Ueber die Entwickelung der grünen Algen unter Ausschluss der

Bedingungen der Kohlensäure-assimilation. Bull. Soc. Imp. Nat. Moscou.

Nouv. sér. XIV. pp. 39-47, 1899.

—— Zur Ernährungsphysiologie der grünen Algen. Ber. Deutsch. Bot. Ges.

XIX. pp. 7-9, 1901.

—— Zur Frage der physiologischen Rassen einiger grüner Algen. Ber.

Deutsch. Bot. Ges. XX. pp. 172-175, 1902.

—— Ueber die Bildung des Chlorophylls durch grüne Algen. Ber. Deutsch.

Bot. Ges. XX. pp. 201-207, 1902².

=Babikoff, J.= Du Développement des céphalodies sur le thallus du lichen

Peltigera aphthosa Hoffm. Bull. Acad. Imp. Sci. St Pétersbourg, XXIV. pp.

548-559 (1 pl.), 1878.

=Babington, Churchill.= Lichenes in the Botany of the Antarctic Voyage by

Joseph Dalton Hooker. II. Flora Novae-Zelandiae, pp. 266-311 (8 pls.).

London, 1855.

=Bachmann, E.= Ueber nichtkrystallisirte Flechtenfarbstoffe, ein Beitrag

zur Chemie und Anatomie der Flechten. Pringsh. Jahrb. Wiss. Bot. XXI. pp.

1-61 (1 pl.), 1890.

—— Der Thallus der Kalkflechten. Wiss. Beil. Realsch. Plauen I. v. 26 pp.

(1 pl.), 1892, and Ber. Deutsch. Bot. Ges. X. pp. 30-37 (1 pl.), 1892.

—— Zur Frage des Vorkommens von ölfuhrenden Sphaeroidzellen bei Flechten.

Ber. Deutsch. Bot. Ges. XXII. pp. 44-46, 1904.

—— Die Beziehungen der Kieselflechten zu ihrem Substrat. Tom. cit. pp.

101-104 (1 pl.), 1904.

—— Die Rhizoidenzone granitbewohnender Flechten. Jahrb. Wiss. Bot. XLIV.

pp. 1-40 (2 pls.), 1907.

—— Die Beziehungen der Kieselflechten zu ihrer Unterlage. II. Granat und

Quarz. Ber. Deutsch. Bot. Ges. XXIX. pp. 261-273 (figs.), 1911. III.

Bergkristall und Flint. Op. cit. XXXV. pp. 464-476, 8 figs., 1917.

—— Der Thallus der Kalkflechten. II. Flechten mit Chroolepusgonidien.

Ber. Deutsch. Bot. Ges. XXXI. pp. 3-12 (1 pl.), 1913.

—— Zur Flechtenflora des Erzgebirges. I. Rittersgrün. Hedwigia, LIII. pp.

99-123, 1913. II. Allenburg. Hedwigia, LV. pp. 157-182, 1914.

=Bachmann, Freda M.= A New Type of Spermogonium and Fertilization in

Collema. Ann. Bot. XXVI. pp. 747-760 (1 pl.), 1912.

—— The Origin and Development of the Apothecium in Collema pulposum.

Arch. Zellforsch, x. 4, pp. 369-430 (7 pls.), 1913.

=Baranetzky, J.= Beitrag zur Kenntniss des selbständigen Lebens der

Flechtengonidien. Bull. Acad. Imp. Sci. St Pétersbourg XII. pp. 418-431

[1867], 1868.

—— Beitrag zur Kenntniss des selbständigen Lebens der Flechtengonidien.

Pringsh. Jahrb. Wiss. Bot. VII. pp. 1-18 (1 pl.), (1868), 1869-70.

=Bary, Anton de.= Morphologie und Physiologie der Pilze, Flechten und

Myxomyceten. Leipzig, 1866.

—— Ueber die Keimung einiger grosssporiger Flechten. Pringsh. Jahrb.

Wiss. Bot. V. pp. 201-216 (3 pls.), 1866-7.

—— Die Erscheinung der Symbiose. Naturf. Vers. Cassel, LI. Tagebl. p.

121, 1879.

—— Vergleichende Morphologie und Physiologie der Pilze. Leipzig, 1884.

=Bauhin, J. and Cherler, J. H.= Historiae Plantarum Universalis I. Lib.

II. Yverdun, 1650.

=Bauhin, Kaspar.= Pinax Theatri botanici, etc. Basle, 1623.

=Baur, Erwin.= Zur Frage nach der Sexualität der Collemaceen. Ber.

Deutsch. Bot. Ges. XVI. pp. 363-367 (1 pl.), 1898.

—— Die Anlage und Entwickelung einiger Flechtenapothecien. Flora,

LXXXVIII. pp. 319-332 (2 pls.), 1901.

—— Untersuchungen über die Entwickelungsgeschichte der Flechtenapothecien

I. Bot. Zeit. LXII. pp. 21-44 (2 pls.), 1904.

=Bayrhoffer.= Einiges über Lichenen und deren Befruchtung. Bern. 44 pp.

(4 pls.), 1851.

=Beckmann, Paul.= Untersuchungen über die Verbreitungsmittel von

gesteinbewohnenden Flechten im Hochgebirge mit Beziehung zu ihrem

Thallusbau. Engler, Bot. Jahrb. XXXVIII. Beibl. pp. 1-72 (10 figs.), 1907.

=Berg, Th.= Zur Kenntniss des in der Cetraria islandica vorkommenden

Lichenins und jodbläuenden Stoffes. Russ. Zeitschr. Pharm. 1873, pp. 129

and 161. See Jahresber. Chemie (1873), p. 848, 1875.

=Berkeley, M. J.= Note on Lecanora esculenta. Gard. Chron. p. 611

(figs.), 1849.

—— Introduction to Cryptogamic Botany. London, 1857.

=Berzelius, J. J.= Versuche über die Mischung des Isländischen Mooses und

seine Anwendung als Nahrungsmittel. Schweigger Journ. VII. pp. 317-352,

1813.

=Beyerinck, M. W.= Culturversuche mit Zoochlorellen, Lichenengonidien und

anderen niederen Algen. Bot. Zeit. XLIII. pp. 725-739, 741-754, 757-768,

781-785 (1 pl.), 1890.

=Beyerinck, M. W.= Das Assimilationsprodukt der Kohlensäure in den

Chromatophoren der Diatomeen. Rec. Trav. Bot. Néerl. I. pp. 28-33, 1904.

=Bialosuknia, W.= Sur un nouveau genre de Pleurococcacées. Bull. Soc.

Bot. Genève. Sér. 2, I. pp. 101-104 (figs.), 1909.

=Bioret, G.= Contributions à l’étude de l’apothécie chez les Graphidées.

Rev. Gén. de Bot. XXVI. pp. 249-252 (1 pl.), 1914.

=Bitter, G.= Ueber das Verhalten der Krustenflechten beim Zusammentreffen

ihrer Ränder. Pringsh. Jahrb. Wiss. Bot. XXXIII. pp. 47-127 (14 figs.),

1899¹.

—— Ueber maschenförmige Durchbrechungen der untern Gewebeschichte oder

des gesammten Thallus bei verschiedenen Laub-und Strauchflechten. Botan.

Untersuch., Festschrift für Schwendener. Berlin, pp. 120-149 (8 figs.),

1899².

—— Ueber die Variabilität einiger Laubflechten und über den Einfluss

äusserer Bedingungen auf ihr Wachsthum. Pringsh. Jahrb. Wiss. Bot. XXXVI.

pp. 421-492 (7 pls. and figs.), 1901¹.

—— Zur Morphologie und Systematik von Parmelia, Untergattung Hypogymnia.

Hedwigia, XL. pp. 171-274 (2 pls., 21 figs.), 1901².

—— Zur Soredienbildung. Hedwigia, XLIII. pp. 274-280, 1904¹.

—— Peltigeren-Studien I und II. Ber. Deutsch. Bot. Ges. XXII. pp. 248 254

(1 pl.), 1904².

=Blackman, V. H.= On the Fertilization, Alternation of Generations, and

General Cytology of the Uredineae. Ann. Bot. XVIII. pp. 323-373 (3 pls.),

1904.

=Blackman, V. H. and Welsford, E. J.= The Development of the Perithecium

of Polystigma rubrum DC. Ann. Bot. XXVI. pp. 761-767 (2 pls.), 1912.

=Bohler, J.= Lichenes Britannici. Sheffield, 1835.

=Bonnier, Gaston.= Recherches expérimentales sur la synthèse des lichens

dans un milieu privé de germes. Comptes Rendus, CIII. p. 942, 1886.

—— Germination des spores des lichens sur les protonémas des Mousses et

sur des Algues différent des gonidies du Lichen. Comptes Rendus Soc.

Biol., Sér. 8, V. pp. 541-543, 1888.

—— Germination des lichens sur les protonémas des Mousses. Rev. Génér.

Bot. I. pp. 165-169 (1 pl.), 1889¹.

—— Recherches sur la synthèse des lichens. Ann. Sci. Nat., Sér. 7, IX.

pp. 1-34 (5 pls.), 1889².

=Bornet, Ed.= Description de trois lichens nouveaux. Mém. Soc. Sci. Nat.

Cherbourg, IV. pp. 225-234 (4 pls.), 1856.

—— Sur les gonidies des Lichens. Comptes Rendus, Paris, LXXIV. p. 820,

1872.

—— Recherches sur les gonidies des Lichens. Ann. Sci. Nat., Sér. 5, XVII.

pp. 45-110 (11 pls. col.), 1873.

—— Deuxième note sur les gonidies des Lichens. Op. cit. XIX. pp. 314-320,

1874.

=Borzi, A.= Intorno agli offici dei Gonidii de Licheni. Nuovo Giorn. Bot.

Ital. VII. pp. 193-204, 1875.

—— Studii sulla sessualità degli ascomiceti. Nuovo Giorn. Bot. Ital. X.

pp. 43-78 (2 pls.), 1878.

=Braconnot, Henri.= De la présence de l’oxalate de chaux dans le règne

minéral; existence du même sel en quantité énorme dans les plantes de la

famille des Lichens, et moyen avantageux d’en extraire l’acide oxalique.

Ann. Chim. Phys. XXVIII. pp. 318-322, 1825.

=Brandt, Theodor.= Beiträge zur anatomischen Kenntniss der

Flechtengattung Ramalina. Hedwigia, XLV. pp. 124-158 (5 pls.), 1906.

=Braun, Fr.= Verzeichniss der in der Kreis.-Nat.-Samml. Bayreuth

Petrefacten. Leipzig. p. 94, 1840.

=Braun, Lucy E.= The vegetation of conglomerate rocks of the Cincinnati

region. Plant World, XX. pp. 380-392, 1917, and Bryologist, XXI. p. 93,

1918.

=Brefeld, Oscar.= Untersuchungen aus dem Gesammtgebiete der Mykologie,

VIII. Leipzig, 1889.

—— Untersuchungen aus dem Gesammtgebiete der Mykologie. Münster, IX.,

1891.

=Brez, Jacques.= La Flore des Insectophiles. Antrecht, 1791.

=Britten J. and Boulger, G. S.= A Biographical Index of British and Irish

Botanists. London, 1893. Suppls. 1899, 1905, 1908.

=Brooks, F. T.= The Development of Gnomonia erythrostoma Pers. Ann. Bot.

XXIV. pp. 585-605 (2 pls.), 1910.

=Brown, Ernest W.= Notes on Cetraria islandica (Iceland Moss). Amer.

Journ. Physiol. I. pp. 455-460, 1898.

=Brown, W. H.= The Development of the Ascocarp of Lachnea scutellata.

Bot. Gaz. LII. pp. 275-305 (figs. and pl.), 1911.

=Buchet, Gaston.= Les Lichens attaquent le verre et, dans le vitreux,

semblent préférer certaines couleurs. C. R. Soc. Biol. Paris, Sér. 9, II.

p. 13, 1890.

=Buddle, Adam.= Hortus siccus Plantarum Angliae, quo continetur curiosa

Muscorum collectio (in Herb. Sloane in Brit. Mus.). 1690-1700.

=Buxbaum, J. C.= Enumeratio Plantarum, etc. Halle, 1721.

—— Plantarum minus cognitarum, complectens Plantas circa Byzantium in

Oriente observatas. Cent. II. St. Petersburg, 1728.

=Calkins, W. W.= An edible lichen not heretofore noted as such. Bot. Gaz.

XVII. p. 418, 1892.

—— The Lichen Flora of Chicago and vicinity. Bull. Geol. Nat. Hist.

Survey. Chicago, 58 pp., 1896.

=Camerarius, Joachimus.= De plantis Epitome utilissima iconibus, etc.

1586.

=Candolle, A. P. de and Lamarck, J. B. P. A. de M. de.= Flore Française,

II. Paris, 1805.

=Carrington, B.= Dr Gray’s Arrangement of the Hepaticae. Trans. Bot. Soc.

Edinb. X. pp. 305-309, 1870.

=Cassini, Henri.= Doutes sur l’origine et la nature du Nostoc. Journ. de

Phys. Chim. Hist. Nat. Paris, LXXXIV. pp. 395-399, 1817.

=Chambers, C. O.= The relation of algae to dissolved oxygen and carbon

dioxide, with special reference to carbonates. Missouri Bot. Gard. Ann.

Rep. 23, pp. 171-207, 1912.

=Chevallier, F.-T.= Histoire des Graphidées. Paris, 1824.

=Chodat, Robert.= On the Polymorphism of the Green Algae and the

Principles of their Evolution. Ann. Bot. XI. pp. 97-121, 1897.

=Chodat, R.= Lichens épiphylles des environs de Genève. Verh. Schweiz.

Naturf. Ges. XCV. pp. 209-210, 1912.

—— Monographies d’Algues en Culture Pure. Berne, 1913.

=Church, A. Herbert.= Food, some account of its sources, constituents,

and uses. South Kensington Museum Science Handbooks, Chapman and Hall,

Piccadilly, 1880.

=Claassen, E.= Caloplaca pyracea, eine Krustenflechte auf den

Sandstein-Fuszsteigen zu East Cleveland, Ohio. Hedwigia, LIV. pp.

217-218, 1914.

=Colonna, Fabio.= Minus cognitarum Stirpium aliquot, ac etiam rariorum

nostro coelo orientium [Ecphrasis], etc. Rome, 1606.

=Comère, J.= Les algues d’eau douce. Paris, 1912.

=Corda, A. C. I.= Icones Fungorum. Prague, 1837-1854; III., 1839.

=Cordus, Valerius.= Historiae Stirpium. Strasburg, 1561.

=Cramer, C.= Ueber das Verhältnis von Chlorodictyon foliosum J. Ag. und

Ramalina reticulata (Noehden). Ber. Schweiz. Bot. Ges. I. pp. 100-123 (3

pls.), 1891.

=Cramer, G. C. P.= De Lichene Islandico (Diss.). Erlangen, 1780.

=Crombie, J. M.= On the Lichen-Gonidia question. Popular Science Review,

18 pp. (1 pl.), July, 1874.

—— Dr Nylander on gonidia and their different Forms (translation).

Grevillea, VI. pp. 39-48, 1877.

=Crombie, J. M.= On the Lichens of Dillenius’s “Historia Muscorum,” as

illustrated by his Herbarium. Journ. Linn. Soc. XVII. pp. 553-581, 1880.

—— On the Algo-Lichen Hypothesis. Journ. Linn. Soc. XXI. pp. 259-283 (2

pls.), 1885.

—— Recent observations of Dr Nylander on Schwendenerism (translation from

Nylander). Grevillea, XX. pp. 60-62, 1891.

—— A Monograph of Lichens found in Britain, I. London, 1894.

=Culpepper, Nicolas.= The English Physician, etc. London, 1652.

=Cunningham, D. D.= On Mycoidea parasitica, a new genus of Parasitic

Algae and the Part which it plays in the Formation of certain Lichens.

Trans. Linn. Soc. Ser. 2, I. p. 301 (1 pl.), 1879.

=Cutting, E. M.= On the Sexuality and Development of the Ascocarp in

Ascophanus carneus Pers. Ann. Bot. XXIII. pp. 399-417 (1 pl.), 1909.

=Czapek, Friedrich.= Biochemie der Pflanzen. 2 vols. Jena, 1905.

=Dangeard, P. A.= Recherches sur la structure des Lichens. Le Botaniste,

Sér. 4, fasc. 1 and 2, 1894.

—— La Reproduction sexuelle des Ascomycètes. Tom. cit. pp. 21-58 (figs.),

1894.

=Danilov, A. N.= Ueber das gegenseitige Verhältnis zwischen den Gonidien

und dem Pilzkomponenten in der Flechtensymbiose. Bull. Jard. Imp. Bot. St

Pétersbourg, X. pp. 34-66 (German Résumé, pp. 66-70), (3 pls.). 1910.

=Darbishire, O. V.= Kritische Bemerkungen über das Microgonidium.

Hedwigia, XXXIV. pp. 181-190, 1895.

—— Dendrographa, eine neue Flechtengattung. Ber. Deutsch. Bot. Ges. XIII.

pp. 313-326 (1 pl.), 1895².

—— Botanische Ergebnisse. Flechten aus dem Umanakdistrikt. Bibliotheca

Botanica, Heft 42, VI. pp. 55-61, 1897.

—— Die deutschen Pertusariaceen mit besonderer Berücksichtung ihrer

Soredienbildung. Engler, Bot. Jahrb. XXII. pp. 593-671, 1897².

—— Monographia Roccelleorum. Bibliotheca Botanica, Heft 45, 103 pp. (30

pls., 29 figs.). Stuttgart, 1898.

—— Ueber die Apothecienentwickelung der Flechte Physcia pulverulenta.

Pringsh. Jahrb. Wiss. Bot. XXXIV. pp. 322-345, 1900.

—— The lichens of the South Orkneys. Trans. and Proc. Bot. Soc.

Edinburgh, XXIII. pp. 1-6 (1 pl.), 1905.

—— Report of the second Norwegian expedition in the Fram 1898-1902, N.

21, Lichens. Kristiania, 68 pp. (2 pls.), 1909.

—— The lichens of the Swedish Antarctic Expedition. Wissenschaftliche

Ergebnisse der Schwedischen Südpolar-Expedition 1901-1903. IV. Lief. 11,

73 pp. 1 fig., (3 pls.), 1912.

—— The Development of the Apothecium in the Lichen Peltigera (abstract).

Trans. Brit. Ass. Adv. Sci. pp. 713-714, 1913.

=Darbishire, O. V. and Fischer-Benzon, R. V.= Die Flechten

Schleswig-Holsteins. Kiel und Leipzig, 1901.

=Davies, Hugh.= Welsh Botanology. London, 1813.

=Dawson, Maria.= On the Biology of Poronia punctata. Ann. Bot. XIV. pp.

245-262 (2 pls)., 1900.

=Deckenbach, Const.= Ueber den Polymorphismus einiger Luftalgen. Scripta

Botanica. Hort. Univ. Imp. Petrop. IV. pp. 32-40 (1 pl.), 1893.

=Delise, D.= Histoire des Lichens. Genre Sticta. Caen, 1822.

=Desfontaines, R. L.= Flora Atlantica, etc. Paris, 1798-1800.

=De-Toni, G. V.= Sylloge Algarum, I. Pavia, 1889.

=Dickson, J. J.= Plantarum Cryptogamicarum Britanniae. 4 Fasc. (Illus.).

London, 1785-1801.

=Dillenius, Johann Jakob.= Catalogus Plantarum sponte circa Gissam

nascentium, etc. Frankfurt am Main, 1719.

—— Ray’s Synopsis Methodica, etc. Ed. 3, 1724.

—— Historia Muscorum. Oxonii (1740), 1741.

=Dodoens, R.= Stirpium historiae pemptades. Antwerp, 1583.

=Dorstenius, Theodoricus.= Botanicon, continens Herbarum, aliorumque

Simplicium, quorum usus in medicinis est, etc. Frankfurt, 1540.

=Druce, G. Claridge and Vines, S. H.= The Dillenian Herbaria. Oxford,

1907.

=Dufrenoy, J.= Les conditions écologiques du développement des

champignons parasites. Bull. Soc. Mycol. France, XXXIV. pp. 8-26, 1918.

=Dundonald, Lord.= Process for extracting a gum from Lichens. Phil. Mag.

London, X. pp. 293-299, 1801.

=Edinburgh Encyclopaedia= (=Brewster’s=). Lichen, XII. pp. 729-741, 1830.

=Egeling, Gustav.= Ein Beitrag zur Lösung der Frage bezüglich der

Ernährung der Flechten. Oesterr. Bot. Zeitschr. XXXI. pp. 323-324, 1881.

=Elenkin, A. A.= Wanderflechten der Steppen und Wüsten. Bull. Jard. Imp.

Bot. St Pétersbourg, I. pp. 16-38 and 52-72 (4 pls., 7 figs.), 1901¹.

—— Les Lichens facultatifs. Bull. Jard. Imp. Bot. St Pétersbourg, I. pp.

129-154 (1 pl. and figs.), 1901². (Russian with French résumé.)

—— Zur Frage der Theorie des “Endosaprophytismus” bei Flechten. Bull.

Jard. Imp. Bot. St Pétersbourg, II. pp. 65-84, 1902.

—— Neue Beobachtungen über die Erscheinungen des Endosaprophytismus bei

heteromeren Flechten. Bull. Jard. Imp. Bot. St Pétersbourg, IV. pp. 25-39

(2 col. pls.), 1904¹.

—— Zur Frage der Theorie des “Endosaprophytismus” bei Flechten. Bull.

Soc. Imp. Nat. Moscou, p. 164, 1904².

—— Notes Lichenologiques. Bull. Jard. Imp. Bot. St Pétersbourg, V. pp.

121-133, 1905.

—— Species novae lichenum in Sibiria arctica, etc. Ann. Mycol. IV. pp.

36-38, 1906¹.

—— Die Symbiose als abstracte Auffassung des beweglichen Gleichgewichts

der Symbionten. (Russian with German résumé.) Bull. Jard. Imp. Bot. St

Pétersbourg, VI. pp. 1-19, 1906².

=Elenkin, A. A. and Woronichin, N. N.= Epiphylle Flechten im Kaukasus.

Trav. Soc. Imp. Nat. St Pétersbourg, XXXIX. pp. 252-258, 1908.

=Elfving, F.= Ueber die Flechtengonidien. Förh. Nordisk. Nat.-forsk. och

Läk. Helsingfors, 1902, 5 pp., 1903. Ann. Mycol. II. pp. 304-305, 1904.

—— Untersuchungen über die Flechtengonidien. Act. Soc. Sci. Fenn. XLIV.

n. 2, 71 pp. (8 pls.), 1913.

=Engelhardt, Hermann.= Flora der Braunkohlenformation im Königreich

Sachsen. Leipzig, 1870.

=Ernst, A.= (=Trans. by A. C. Seward=). The new Flora of the volcanic

Island of Krakatau. Cambridge, 1908.

=Errera, Leo.= Ueber den Nachweis des Glykogens bei Pilzen in Bot. Zeit.

XLIV. pp. 316-320, 1886.

—— “Pain du ciel” provenant de Diarbekir. Bull. Acad. Roy. Belg. Sér. 3,

XXVI. pp. 83-91, 1893.

—— L’épiplasme des Ascomycetes et le glycogène des végétaux (Thèse.

Bruxelles, 1882). Rec. Inst. Bot. Univ. Brux. I. pp. 1-70, 1906.

=Eschweiler, F. G.= Systema Lichenum, genera exhibens, etc. Nuremberg (1

pl.), 1824.

=Escombe, F.= Chemistry of Lichenic and Fungal Membranes. Ann. Bot. X.

pp. 293-294, 1896.

—— Beitrag zur Chemie der Membranen der Flechten und Pilze. Zeitschr.

Physiolog. Chemie, XXII. p. 288, 1896.

=Etard and Bouilhac.= Présence des chlorophylles dans un _Nostoc_ cultivé

à l’abri de la lumière. Comptes Rendus, CXXVII. pp. 119-121, 1898.

=Ettingshausen C. and Debey, M. H.= Die urweltlichen Thallophyten des

Kreidegebirges von Aachen und Maestricht. Sitzungsb. K. Akad. Wiss. Wien,

pp. 507-512, 1857; and Bull. Soc. Bot. France, V. pp. 304-306, 1858.

=Euler, H.= Grundlagen und Ergebnisse der Pflanzenchemie. Braunschweig,

1908.

=Eversmann, E.= In Lichenem esculentum Pallasci. Nova Acta Leop. XV. pp

349-362 (1 pl.), 1825.

=Famintzin, A.= Die Symbiose als Mittel der Synthese von Organismen.

Biol. Centralbl. XXVII. p. 353, 1907.

=Famintzin, A. and Baranetzky, J.= Zur Entwickelungsgeschichte der

Gonidien und Zoosporenbildung der Flechten. Mém. Acad. Imp. Sci. St

Pétersbourg, Sér. 7, XI. No. 9, 7 pp. (1 pl.) (1867), 1868. Ann. Sci.

Nat., Sér. 5, VIII. pp. 137-144 (1 pl.), 1867.

=Faull, J. H.= The Cytology of the Laboulbeniales. Ann. Bot. XXV. pp.

649-654, 1911.

=Fée, A. L. A.= Essai sur les Cryptogames des écorces exotiques

officinales. Paris, 1824.

—— Matériaux pour une Flore Lichénologique du Brésil. Bull. Soc. Bot. Fr.

XX. pp. 307-319, 1873.

=Fink, Bruce.= Lichens of Minneapolis and Vicinity. Minn. Bot. Stud. I.

pp. 703-725, 1894.

—— Contributions to a knowledge of the lichens of Minnesota, I.-VII.

Minn. Bot. Stud. I.-III., 1896-1903.

—— Lichens of the Lake Superior region. Minn. Bot. Stud. II. pp. 215-276,

1898-1902.

—— Lichens of the Minnesota Valley. Tom. cit. pp. 277-329².

—— Lichens of N. W. Minnesota. Tom. cit. pp. 657-709³.

—— Lichens of the Northern Boundary. Op. cit. III. pp. 167-236, 1903.

—— Composition of a Desert Lichen Flora. Mycologia, I. pp. 87-109, 1909.

—— Some Common Types of Lichen Formations. Torrey Bot. Club, XXX. pp.

412-418, 1903.

—— A Lichen Society of a Sandstone Rip-rap. Bot. Gaz. XXXVI. pp. 265-284

(5 figs.), 1904.

—— The Nature and Classification of Lichens. I. Mycologia, III. pp.

231-269, 1911; II. Op. cit. V. pp. 97-116, 1913.

—— The rate of Growth and Ecesis in Lichens. Mycologia, IX. pp. 138-158,

1917.

—— A new genus and species of the Collemaceae. Mycologia, X. pp. 235-238

(1 pl.), 1918.

=Fischer, Ed.= Beiträge zur Kenntniss exotischen Pilze. Hedwigia, XXIX.

pp. 161-171 (1 pl.), 1890.

=Fitting, N.= Ueber die Beziehungen zwischen den epiphyllen Flechten und

den von ihnen bewohnten Blättern. Ann. Jard. Bot. Buitenzorg, Suppl. 3,

pp. 505-519, 1910.

=Fitzpatrick, Henry Morton.= Sexuality in Rhizina undulata. Bot. Gaz.

LXV. pp. 201-226 (2 pls.), 1918.

=Flagey, C.= Lichenes algeriensis exsiccati. Rev. Mycol. XIII. pp. 83-87

and 107-117, 1901; pp. 70-79, 1892.

—— Catalogue des Lichens. Battandier and Trabut, Flore de l’Algérie.

Algiers, Part 2, I. pp. XII. and 139, 1896.

=Flörke, H. G.= Deutsche Lichenen. 10 Lief. Berlin, 1815-19.

—— De Cladoniis, etc. Rostock, 1828.

=Flotow, Julius von.= Mikroskopische Flechtenstudien. Bot. Zeit. VIII.

pp. 361-369, 377-382, 1850.

=Forskål, P.= Descriptiones Plantarum Florae Aegyptiaco-Arabicae (5).

Hauniae, 1775.

=Forssell, K. B. J.= Studier öfver Cephalodierna. Bihang K. Svensk.

Vet.-Akad. Handl. VIII. n. 3, 112 pp. (2 pls.), 1882.

=Forssell, K. B. J.= Lichenologische Untersuchungen. I. Ueber die

Cephalodien. Flora, LXVII. pp. 1-8, 33-46, 58-63, 177-193, 1884.

—— Anatomie und Systematik der Gloeolichenen. Nov. Act. Reg. Soc. Sci.

Upsal. Sér. 3, 118 pp., 1885¹.

—— Die anatomische Verhältnisse und die phylogenetische Entwicklung der

Lecanora granatina Sommerf. Bot. Centralb. XXII. pp. 54-58 and 85-89,

1885².

—— Ueber den Polymorphismus der Algen (Flechtengonidien), etc. Flora,

LXIX. pp. 49-64, 1886.

=Forster, T. F.= Flora Tonbrigensis. London, 1816.

=Frank, A. B.= Ueber die biologischen Verhältnisse des Thallus einiger

Krustenflechten. Cohn’s Beiträge zur Biologie der Pflanzen, II. pp.

123-200 (1 pl.), 1876.

=Fraser, H. C. I.= On the Sexuality and Development of the Ascocarp in

Lachnea stercorea Pers. Ann. Bot. XXI. pp. 349-360 (2 pls.), 1907.

=French, G. H.= Mounting Lichens. Journ. Applied Microscopy: Rochester N.

Y. I. p. 135, 1898.

=Friederich, Albert.= Beiträge zur Anatomie der Silikatflechten.

Fünfstück’s Beitr. Wiss. Bot. V. pp. 377-404, 1906.

=Fries, Elias.= Systema orbis vegetabilis, I. Lund, 1825.

—— Primitiae Geographiae Lichenum. Lund, 1831.

—— Lichenographia Europaea reformata. Lund, 1831.

=Fries, Th. M.= Monographia Stereocaulorum et Pilophororum. Act. Reg.

Soc. Sci. Upsala, Ser. 3, II. pp. 307-380 (4 pls.), 1858.

—— Genera Heterolichenum Europeae recognita. Upsala, 1861.

—— Lichenes Arctoi. Nova Act. Soc. Sci. III. pp. 103-398, 1861.

—— Beiträge zur Kenntniss der sogenannten Cephalodien bei den Flechten.

Flora, XLIX. pp. 17-25, 1866.

—— Lichenes Spitsbergenses. K. Sv. Vet.-Akad. Handl. VII. n. 2, 1867.

=Fritsch, F. E.= The Rôle of Algal Growth in the colonization of new

ground, etc. Geographical Journal, XXX. pp. 531-547, 1907.

=Fuisting, W.= Beiträge zur Entwickelungsgeschichte der Lichenen. Bot.

Zeit. XXVI. pp. 641, etc. (1 pl.), 1868.

=Fünfstück, M.= Beiträge zur Entwickelungsgeschichte der Lichenen.

Eichler’s Jahrb. ot. Gart. Berlin, III. pp. 155-174 (3 pls.), 1884.

—— Die Fettabscheidung der Kalkflechten in Fünfstück’s Beitr. Wiss. Bot.

I. pp. 157-220 (3 pls.), 1895 and Nachtrag, pp. 316-321, 1896.

—— Lichenes (Allgemeiner Teil). Engler und Prantl, Die Natürlichen

Pflanzenfamilien, I. 1*, pp. 1-48, 1898.

—— Weitere Untersuchungen über die Fettabscheidung der Kalkflechten. Bot.

Untersuch., Festschrift für Schwendener, pp. 341-356. Berlin, 1899.

—— Der gegenwärtige Stand der Flechtenforschung nebst Ausblicken auf

deren voraussichtliche Weiterentwickelung. Ber. Deutsch. Bot. Ges. XX.

19te General-Versammlung, pp. 62-77, 1902.

=Galløe, O.= Danske Likeners Ökologi. Botan. Tidsskrift, XXVIII. pp.

285-372 (3 pls.), 1908.

—— Forberedende Undersøgelser til en almindelig Likenølogi. Dansk

Botanisk Arkiv, I. n. 3, 119 pp. (240 figs.), 1913-15.

=Garjeaune, A. J. M.= Die Verpilzung der Lebermoosrhizoiden. Flora, CII.

pp. 147-185 (2 pls. and figs.), 1911.

=Gautier, Armand.= Présence de l’iode en proportions notables dans

tous les végétaux à chlorophylle de la classe des Algues et dans les

sulfuraires. Comptes Rendus, CXXIX. pp. 191-194, 1899.

=Georgi, I. G.= Scrutamen chemicum Lichenum parasiticorum. Acta Acad.

Sci. Imp. Petropol. III. Pars II. pp. 282-292 [1779], 1783.

=Gerard, John.= The Herball or generall historie of Plantes, etc. London,

1597.

=Gibelli, Giuseppe.= Sugli Organi Riproduttori del genere Verrucaria.

Memorie della Soc. Ital. Sci. Nat. Milano, I. n. 5 (1 pl.), 1866.

=Gilson, E.= La cristallisation de la cellulose et la composition

chimique de la membrane cellulaire végétale. La Cellule, IX. fasc. 2,

1893.

—— Recherches chimiques sur la membrane cellulaire des Champignons. La

Cellule, XI. fasc. 1. pp. 7-15, 1894.

=Gleditsch, J. G.= Einleitung in die neuere Forstwissenschaft, I. Berlin,

1775.

=Glück, Hugo.= Entwurf zu einer Vergleichenden Morphologie der

Flechten-Spermogonien. Verh. Naturhist.-Med. Ver. VI. 2. Heidelberg, pp.

vi. and 136 (2 pls.), 1899.

=Gmelin, J. F.= Systema Naturae, II. Leipzig, 1791.

=Gmelin, J. G.= Reise durch Sibirien. Göttingen, 1752.

=Goeppert, H. R.= Uebersicht der fossilen Flora Schlesiens 1844-45 (in

Wimmer’s Flora von Schlesien, Breslau, 1845).

—— Ueber den Einfluss der Pflanzen auf felsige Unterlage. Flora, XLIII.

pp. 161-171, 1860.

=Goeppert, H. R. and Menge, A.= Die Flora des Bernsteins, I. Danzig, 1883.

=Gray, S. F.= A Natural Arrangement of British Plants, I. London, 1821.

=Greville, R. K.= Scottish Cryptogamic Flora, etc. I.-VI. Edinburgh,

1823-28.

—— Flora Edinensis. Edinburgh, 1824.

=Guembel, C. W.= Mittheilungen über die neue Färberflechte Lecanora

ventosa Ach. Denkschr. K. Akad. Wiss. Math.-Natur. Cl. Wien, XI. Abth. 2,

pp. 23-40 (1 pl.), 1856.

=Guérin-Varry, R. J.= Mémoires sur deux Produits naturels de la

Végétation considérés comme des Gommes. Ann. Chim. Phys. Sér. 2, LVI. pp.

225-252, 1834.

=Guilliermond, A.= Formation des Asques et de l’épiplasme des

Ascomycètes. Rev. Gén. Bot. XVI. pp. 49-66, 1904.

=Haberlandt, G.= Ueber die Beziehungen zwischen Function und Lage des

Zellkernes bei den Pflanzen. Jena, pp. viii, 135 (2 pls.), 1887.

—— Physiologische Pflanzenanatomie, ed. 2. Leipzig, 1896.

=Haller, Alb. von.= Enumeratio Methodica Stirpium Helvetiae indigenarum,

etc. Göttingen, 1742.

—— Historia Stirpium indigenarum Helvetiae, III. Berne, 1768.

=Halsey, A.= Synoptical view of the Lichens, growing in the vicinity of

the city of New York. Ann. Lyceum Nat. Hist. New York, I. pp. 3-21, 1824.

=Hamlet, W. M. and Plowright, C. B.= On the occurrence of Oxalic Acid in

Fungi. Chemical News, XXXVI. pp. 93-94, 1877.

=Harmand, J.= Lichens de France. Fasc. I. II. 1905; III. 1907; IV. 1909;

V. 1913.

=Harper, R. A.= Cell-Division in Sporangia and Asci. Ann. Bot. XIII. pp.

467-525, 1899.

—— Sexual reproduction in Pyronema confluens, etc. Ann. Bot. XIV. pp.

321-400 (3 pls.), 1900.

=Hassall, A. H.= A History of the British Freshwater Algae. London, 1845.

=Hedlund, T.= Kritische Bemerkungen über einige Arten der

Flechtengattungen Lecanora, Lecidea und Micarea. Bih. K. Svensk.

Vet.-Akad. Handl. XVIII. Afd. III. n. 3. 104 pp. (1 pl.), 1892.

—— Ueber Thallusbildung durch Pyknokonidien bei Catillaria denigrata und

C. prasina. Bot. Centralbl. LXIII. pp. 9-16, 1895.

=Hedwig, Johann.= Microscopisch-Analytische Beschreibungen und

Abbildungen neuer und zweifelhafter Laub-Moose, II. Leipzig, 1789.

—— Theoria generationis et fructificationis plantarum cryptogamicarum. St

Petersburg, 1784. Enlarged edition. Leipzig, 1798.

=Hellbom, P. J.= Norrlands Lafvar. K. Svensk. Vet.-Akad. Handl. XX. n. 8.

131 pp., 1884.

=Hellbom, P. J.= Lichenaea Neo-Zeelandica, etc. Bihang K. Svensk.

Vet.-Akad. Handl. XXI. Afd. III. n. 13, 150 pp., 1896.

=Henneguy, Félix.= Les Lichens Utiles. Paris, 114 pp. (20 figs.), 1883.

=Herbal.= The Grete Herball, etc., translated from the French, printed by

Peter Treveris. London, 1526.

=Herberger, J. E.= Ueber den Bitterstoff des isländischen Mooses

(Cetraria islandica). Buchner’s Repertorium für Pharmacie, XXXVI. pp.

226-237, 1830.

=Herissey, H.= Sur la présence de l’émulsine dans les Lichens. Comptes

Rendus Soc. Biol. Sér. 10, V. pp. 532-534, 1898; Bull. Soc. Mycol.

France, XV. pp. 44-48, 1899.

=Herre, A. C.= The growth of Ramalina reticulata. Bot. Gaz. XXXVIII. pp.

218-219, 1904.

—— Suggestions as to the origin of California’s Lichen Flora. Plant

World, XIII. pp. 215-220, 1910.

—— The Gyrophoraceae of California. Contrib. U.S. Nat. Herb. XIII. 10,

pp. 313-321 (5 pls.), 1911¹.

—— The desert Lichens of Reno, Nevada. Bot. Gaz. LI. pp. 286-297, 1911².

=Hesse, O.= Beitrag zur Kenntniss der Flechten und ihrer

charakteristischen Bestandteile, 9 Mitth. Journ. prakt. Chem. LXX. pp.

449-502, 1904.

=Hicks, J. Braxton.= Contributions to the knowledge of the Development

of the Gonidia of Lichens in relation to the Unicellular Algae. Quart.

Journ. Micros. Sci. VIII. p. 239, 1860. New series, I. p. 15, 1861.

—— Observations on the Gonidia and Confervoid Filaments of Mosses, and

on the relation of their Gonidia to those of Lichens and of certain

freshwater Algae. Trans. Linn. Soc. London, XXIII. pp. 567-588 (2 pls.),

1862.

=Hill, Sir John.= History of Plants. London, 1751.

—— Flora Britannica. London, 1760.