FUNGI.
The Fungi form the lowest class of plants: as examples of them, may be
mentioned mushrooms, toadstools, puff-balls, the mould of paste, the
blue mould of cheese, &c. The more minute Fungi are very common, forming
beautiful microscopic objects, although they are rarely studied by the
microscopic observer.
Fungi live usually upon rotting or decaying vegetable substances, as
rotten wood, the dead leaves and stems of plants, &c.; but sometimes
they are found upon living plants, and some of them exist upon decaying
animal matters, and even in living animals.
Fungi exhibit no separation of root, stem, or leaves, as exists in the
higher plants; nor do they contain chlorophyll, the presence of which is
so generally associated with the idea of a plant. But they consist of
aggregations of mostly elongate cells, forming branched and interlacing
colourless fibres, buried like roots in the substance (matrix) upon
which they grow, and from which they derive their nourishment; this
portion of the Fungus is called the _mycélium_ (μὑκης, a fungus). The
portion of the Fungus projecting beyond the surface of the matrix is the
fructification; and this is the part usually called the fungus, the
mycelium being overlooked by a casual observer. So that here we have a
character distinguishing the Fungi from the Lichens, which derive their
nourishment from the air, and not from the matrix. The absence of the
green cells, or gonidia, forms another character by which the nearly
allied members of this class of plants can be distinguished.
PLATE VII. [PAGE 96.]
FUNGI.
Fig.
1. _Agaricus micaceus_: _a_, gills.
2. _Agaricus campestris_: _a_, spores; _b_, basidia.
3. _Physarum album_, on a piece of stick.
4. _Physarum album_, spores.
5. _Uredo segetum_, spores.
6. _Uredo caries_, spores.
7. _Uredo candida_, on leaf of Shepherd’s Purse (_Capsella_): _s_,
spores.
8. _Æcidium grossulariæ_, sorus.
9. _Æcidium grossulariæ_: _p_, spore-capsules (peridia); _s_,
anther-capsules (spermogonia).
10. _Nemaspora crocea_: _a_, spores.
11. _Torula casei._
12. _Torula herbarum_, on a piece of stick.
13. _Torula herbarum_, spores.
14. _Phragmidium bulbosum_, on bramble-leaf.
15. _Phragmidium bulbosum_, stylo-spores and paraphyses.
16. _Puccinia graminis_, on a piece of straw.
17. _Puccinia graminis_, spores.
18. _Sporocybe alternata_, filament and spores.
19. _Botrytis parasitica_, on Shepherd’s Purse.
20. _Botrytis parasitica_, spores and filaments.
21. _Rhinotrichum_, species of.
22. _Rhinotrichum_, heads of spores.
23. _Rhinotrichum_, spores detached.
24. _Rhinotrichum_, spores.
25. _Penicillium glaucum._
26. _Penicillium glaucum_, head of spores.
27. _Coremium leucopus._
28. _Tubercularia vulgaris._
29. _Tubercularia vulgaris_, divided receptacle.
30. _Tubercularia vulgaris_, filaments.
31. _Tubercularia vulgaris_, spores.
32. _Sphæria fragiformis._
33. _Trichothecium roseum_, on a piece of stick.
34. _Trichothecium roseum._
35. _Trichothecium roseum_, filaments and spores.
[Illustration: Plate VII.
W Bagg sculp
_London: John Van Voorst._]
The fructification of the Fungi occurs in two distinct forms, in one of
which the seeds or spores are naked, and situated at the ends of slender
cells or filaments, whilst in the other the spores are contained in
usually flask-like cells, called asci, similar to those occurring in the
Lichens. In a few Fungi, antheridial organs, called spermogonia, as in
the case of the Lichens, have also been detected. The Fungi are divided
into six Orders, from each of which a few species may be selected to
illustrate their structure more in detail.
HYMENOMYCE´TES (ὑμἠν, membrane, μὑκης, fungus). This is the highest
Order of Fungi, containing a large number of genera and species; as
examples of which may be mentioned the common Mushroom, Toadstools, &c.
Their general structure may be illustrated by the examination of the
common Mushroom (_Agar´icus campes´tris_); the species figured (Pl. VII.
fig. 1), however, being _Agaricus micáceus_, which is common at the root
of trees, the bottom of decaying posts, &c.
The vegetative part of the fungus consists of a cotton-like mycelium,
which is composed of slender, colourless, interwoven filaments,
popularly known as the spawn. The portion commonly called the mushroom
corresponds to the fructification, and consists of certain parts visible
to the naked eye. These are an expanded portion at the top, forming a
hemispherical cap, receptacle, or _píleus_ (_pileus_, a cap), and a
stalk, or _stípes_, upon which the cap is supported. On the under
surface of the cap are a number of nearly parallel, radiating,
dark-coloured plates or _gills_, somewhat resembling the gill-plates of
a fish. The dark colour of the gills arises from the presence of the
spores, which are coloured, although in some species they are white. The
surface of the gills, upon which the spores are situated, is called the
_hyménium_ (ὑμἠν, membrane). The spores (Pl. VII. fig. 2 _a_) are
microscopic and very minute, and are situated at the ends of little
stalks or points (Pl. VII. fig. 2 _b_), called _sterig´mata_ (στἡρυγμα,
a prop), which are four in number, and consist of prolongations of the
colourless cells of the hymenium; and these cells are the _basid´ia_
(βασἱδιον, a little base). The detection of the basidia requires great
care, as they are very minute and transparent; the best way to observe
them is to cut a very small portion from the uninjured edge of one of
the gills with a fine pair of scissors, and to examine it in water. If
the gills have been bruised, the spores are easily rubbed off, and their
connexion with the basidia destroyed.
In the young state of the Mushroom, the fructification appears as little
knobs upon the spawn or mycelium. Upon cutting these through
perpendicularly, the cap and stalk are found to be enclosed in a skin or
wrapper, called the _vol´va_ (_volva_, a wrapper), and the margin of the
cap is continuous with the surface of the stalk, the connecting membrane
forming the _veil_, or _vélum_ (_velum_, a veil). As the Fungus grows,
the cap rises and bursts the volva, which withers and disappears; and
the veil is torn through, the portion remaining in connexion with the
stalk encircling it as a collar or ring (_an´nulus_).
_Merúlius lach´rymans_, the Dry-rot Fungus, which belongs to the same
family (Agaricíni) as the Mushroom, deserves notice from its very
destructive action upon decaying timber. The filaments of the mycelium
may readily be detected in the rotting wood by examining a thin section
in water. The receptacle forms a yellowish-orange or brownish flattened
mass, some inches in breadth, with white downy margins; and the surface
exhibits folds arranged so as to form large irregular pores, instead of
gills as in the Mushroom.
In other families the cap and stalk appear fused together and
undistinguishable; or the fructification assumes the form of the cap or
the stalk only, and the hymenium does not form gills. Thus in the family
Polyporei (the members of which are common on the trunks of trees and on
rotten posts, and some of which are very large) the basidia are situated
upon the inner surface of tubes immersed in the under part of the mass,
their orifices forming minute pores, yet visible to the naked eye. In
other families the basidia are placed upon the outer surface of a
club-shaped or branched receptacle (Clavarini), or upon external
prickle-like points (Hydnei), &c.
In the family Tremellini the receptacle forms a gelatinous mass, and the
basidia are situated upon its surface, terminating the filaments of
which it is composed. One species, _Dacrymy´ces stillátus_, is very
common on fir posts in the winter and spring, forming little roundish,
yellowish-orange, cushion-like masses.
GASTEROMYCE´TES (γαστἠρ, belly, hollow, μὑκης, fungus).--This order of
Fungi, which contains the Puff-balls and many others not readily
procured, must be very briefly noticed. The spores are contained in a
capsule or perid´ium (πηρἱδιον, a little bag) which is often of large
size, and are situated upon a hymenium forming folds, partitions
(septa), or a lattice-work.
A small species, _Physárum album_ (Pl. VII. fig. 3), is often found
growing upon rotten stems of plants and decaying sticks. The capsules
are minute, grey, brittle, and black within, from the presence of the
spores (fig. 4), which are lens-shaped, and arise from the ends of short
filaments.
CONIOMYCE´TES (κὁνις, dust, μὑκης, fungus).--This Order contains some
beautiful microscopic Fungi, several of which are very common. Many of
them grow upon living plants, while others are found upon decaying
stems, sticks, &c. The mycelium consists of inconspicuous, fine
filaments, which run beneath the epidermis and bark of leaves and stems,
or exist in the intercellular passages, the fruit bursting through the
surface. The spores are short-stalked, forming _sty´lospores_ (στῦλος,
stalk, σπὁρος, seed) or _conid´ia_ (κονἱδιον, little dust). But there is
great confusion in the descriptions of the spores of the same Fungus by
different botanical authors, some describing the fruit (in Pl. VII. fig.
15, for instance) as composed of rows of spores, while others regard it
as forming a single septate (_septum_, a partition) or partitioned
spore.
_Tor´ula herbárum_ (Pl. VII. fig. 12) is very common on the decaying
stems of plants, especially those belonging to the Parsley order
(Umbelliferæ), forming greenish-black streaks or patches. The spores
(fig. 13) are grouped into chains or beaded (moniliform) rows, with very
short stalks, and these are crowded to form the black patches visible to
the naked eye. Under the microscope the spores appear of a brown colour.
_Torula cásei_ (Pl. VII. fig. 11) forms reddish or white patches upon
decaying cheese. It consists of branched, interwoven, tufted filaments
(_flocci_), with comparatively large spherical spores arranged in rows
at their ends.
_Nemas´pora crócea_ (Pl. VII. fig. 10) is a very curious member of this
Order, and is found upon decaying beech-sticks. It appears as an
orange-coloured tendril-like gelatinous mass of spores, bursting through
a little pore on the surface of the bark. The spores (fig. 10 _a_) are
very minute, slender, and curved, and under a high power appear jointed.
_Æcid´ium grossuláriæ_ (Pl. VII. fig. 8) is found very commonly on the
leaves of the gooseberry-bush. It forms to the naked eye oval or rounded
spots (_sori_), of a red colour; and on close examination, the spots
appear dotted with yellow points. Each point is the orifice of an open
capsule (_peridium_), which has burst through the epidermis of the leaf
(Pl. VII. fig. 9 _p_). The capsules are split or lacerated at the
margins, and form little cups containing the spores. The spores are very
minute, yellow, and are arranged in closely packed moniliform rows. The
red colour depends upon the altered chlorophyll of the leaf. On the
leaves containing the spore-capsules or peridia will be found smaller,
brownish-yellow capsules (_spermogonia_) partly imbedded in their
substance (Pl. VII. fig. 9 _s_). These contain minute filaments
(_sterigmata_), terminated by short rows of rounded cells (_spermatia_),
which are supposed to exert an antheridial function. The species of
_Æcidium_ are very numerous, and many of them are extremely common--as
those upon the nettle, the barberry, the dandelion, the wood-anemone,
the violet, and buttercups. The groups of capsules form exquisite opake
objects under a low power of the microscope.
_Phragmid´ium bulbósum_ (Pl. VII. fig. 14) is another very beautiful
coniomycetous Fungus. It forms little reddish, afterwards sooty dots
upon the under surface of the leaves of various species of Bramble
(_Rúbus_). The oblong spores (fig. 15) are from 2-to 4-septate, and
stalked, the stalks being swollen or bulbous at the base. The spores,
which appear brown when magnified, are covered with little knobs
(tuberculate) on the surface; and the uppermost little spore or
sporidium is terminated by a minute point (apiculate). Among the spores
are numerous barren filaments or paraphyses.
_Puccin´ia gram´inis_ (Pl. VII. fig. 16) is to be found everywhere upon
damp rotting straw, and upon grasses. It forms sooty irregular streaks,
consisting of densely crowded, one-partitioned (uniseptate) spores (fig.
17), which appear brown under the microscope. This Fungus is sometimes
called “mildew.” There are numerous other species of _Puccinia_ which
occur upon common plants.
_Urédo seg´etum_ is the “smut” of wheat, barley, and oats--a fungus too
well known to the farmer. It forms sooty masses, bursting through the
epidermis of the stalk and ears of the corn, and soiling the fingers
when handled. The spores (Pl. VII. fig. 5) are exceedingly minute, and
the stalks are so slender and loosely connected with them that they are
not readily detected. Under the microscope the spores appear brown and
faintly dotted, this appearance arising from a reticulated structure of
the surface, similar to that of the poppy-seed on a very small scale.
_Urédo cáries_ is the “bunt” of corn. It grows within the grain, filling
it with a sooty, fœtid mass. The spores (Pl. VII. fig. 6) are
considerably larger than those of the last species, and their surface is
distinctly reticulated. They are attached to the filaments of the
mycelium, as in _Uredo segetum_.
The spores of both these species of _Uredo_ may be found in most kinds
of flour and bread, especially in those of inferior quality.
_Urédo can´dida_ (Pl. VII. fig. 7) is another species, forming white
dots upon the leaves of the common Shepherd’s Purse (_Capsel´la bur´sa
pastor´is_)--which is easily recognized by the form and arrangement of
the pods (fig. 19). The spores (_s_) are rather large and white.
Other species of _Uredo_ are very common upon numerous species of weeds
or wild flowering plants; and they so closely resemble each other that,
when one is known, the others are easily recognized. Usually each
species occurs upon a distinct species of plant, as is the case with
parasites generally. In many of them the spots (_sori_) exhibit a thin
membrane covering the spores, which bursts down the middle, so as to
bear some resemblance to a capsule. But there is no true capsule, the
membrane consisting of the epidermis of the leaf or stalk of the plant,
which is raised and torn by the expansion of the growing fungus; so
that the peridium is spurious, as belonging to the matrix, and not to
the fungus. It may be mentioned here that the so-called species of
_Uredo_ are not truly distinct species, but are the forms of species of
_Puccinia_, _Phragmidium_, &c.; so that the latter genera have two kinds
of fruit, one of which is a _Uredo_, the other a _Puccinia_. But I must
refer to the Dictionary for further details upon this point.
HYPHOMYCE´TES (ὑφἁω, to weave, μὑκης, fungus). In this, the 4th Order of
Fungi, are contained many of the commonest moulds which are found
growing upon decaying substances, and sometimes upon living plants. The
mycelium creeps among the particles of the substance, or the elements of
the tissues, upon which the Fungus lives, in the form of slender threads
or filaments. The spores, which are either simple or partitioned
(septate), and naked, occur either singly or in rows at the ends of fine
interwoven cottony threads or _floc´ci_ (_floc´cus_, a flock of wool),
which are generally very evident to the naked eye. The threads
supporting the spores form the _ped´icels_ (_pedicel´lus_, a little
foot). In technical descriptions, these filaments, which are usually
composed of cells arranged end to end, are said to be _septate_ (Pl.
VII. fig. 26), and not jointed, as in the case of the filaments of the
_Confervæ_, which are constructed in a similar manner. When not septate,
the filaments are said to be _continuous_.
STILBA´CEI.--To this family belongs _Tuberculária vulgaris_ (Pl. VII.
fig. 28), which is found upon decaying sticks and branches of trees,
especially the lime-tree. It forms little firm red knobs or tubercles,
each of which is a receptacle. On making a section of a receptacle (Pl.
VII. fig. 29), the interior is seen to be paler than the bright red
surface, and a short broad stalk comes into view. The receptacle is
composed of crowded cell-filaments, so short near the base as rather to
resemble cellular tissue (fig. 30); but towards the surface the
filaments become extremely slender and branched; and each branch is
terminated by a minute oblong spore, or a short row of them (fig. 31).
If a stick with this Fungus upon it be kept for some time in a damp
place, short whitish fibres, branched at the ends, and visible to the
naked eye, will be seen sprouting from around the base of the receptacle
(Pl. VIII. fig. 1). These, when examined under the microscope, appear
composed of fine filaments (Pl. VIII. fig. 2), resembling those of
_Tubercularia_, and having the minute spores at the ends. After a
considerable time, the entire receptacle of the _Tubercularia_ becomes
resolved into these fibres. In this state the Fungus assumes the
characters of an _Isária_, a genus of a different family of Fungi
(_Isariacei_), so that we have here an _Isaria_-form of _Tubercularia_.
Sometimes the tubercles of the _Tubercularia_ become darker, almost
black, harder, and granular on the surface. On making a section of them
in this state, the whole of the under portion of the surface is found to
contain little roundish capsules, containing asci and spores, and it
constitutes _Sphæ´ria fragifor´mis_ (Pl. VII. fig. 32). As the _Sphæria_
is the more complex and highly organized condition of this Fungus, the
other two conditions must be regarded as forms, and not as species of
separate genera.
DEMATIE´I.--In this family the filaments upon which the spores are
placed are not compacted as in _Tubercularia_, but separate; and they
are of a dark brown or black colour.
_Sporoc´ybe alternáta_ (Pl. VII. fig. 18) is occasionally found upon
decaying vegetable substances, forming little black velvety spots or
patches. The mycelial filaments are exceedingly minute, septate,
tapering at the ends, and terminated by a little tuft of pear-shaped
cells, from which the black simple spores arise singly.
PLATE VIII. [PAGE 104.]
FUNGI.
Fig.
1. _Isaria_-form of _Tubercularia_.
2. _Isaria_-form of _Tubercularia_, filaments.
3. _Aspergillus glaucus._
4. _Aspergillus glaucus_, filaments and heads of spores; _a_, separate
spores.
5. _Aspergillus glaucus_, head of spores.
6. _Peziza omphalodes._
7. _Peziza stercorea._
8. _Peziza stercorea_, cup (receptacle).
9. _Peziza stercorea_, asci and paraphyses.
10. _Peziza stercorea_, divided receptacle.
11. _Peziza stercorea_, bristles.
12. _Dothidea typhina_, on leaf-stalk ofgrass.
13. _Dothidea typhina_, surface of patch (stroma).
14. _Dothidea typhina_, capsules (perithecia).
15. _Dothidea typhina_, ascus containing spores.
16. _Sphæria rubella_, on nettle-stem.
17. _Sphæria rubella_, asci.
18. _Sphæria rubella_, capsules (perithecia).
19. _Sphæria rubella_, ascus and spores.
20. _Sphæria bullata_, on piece of stick; 20 _a_, section of tubercle
(receptacle).
21. _Sphæria bullata_, asci and spores.
22. _Sphæria complanata_, on piece of stick.
23. _Sphæria complanata_, tubercles (receptacles).
24. _Dothidea ulmi_, on elm-leaf.
25. _Dothidea ulmi_, asci.
26. _Dothidea ulmi_, section of receptacle.
27. _Dothidea ulmi_, spores.
28. _Chætomium elatum_; 28 _a_, spores; 28 _b_, filaments.
29. _Chætomium elatum_, on piece of stick.
30. _Hysterium fraxini_, on piece of stick.
31. _Hysterium fraxini_, receptacle.
32. _Hysterium fraxini_, ascus with spores.
33. _Erysiphe guttata_, on hazel-leaf.
34. _Erysiphe guttata_, capsule.
35. _Erysiphe guttata_, capsule (conceptacle) with fulcra.
36. _Mucor mucedo_: _a_, columella; _s_, spores.
37. _Acrostalagmus_: _a_, spores.
38. Gall on oak-leaf.
39. Gall on oak-leaf.
[Illustration: Plate VIII.
_W Bagg sculp_
_London: John Van Voorst._]
MUCED´INES.--Many of the Fungi belonging to this family are extremely
common on decaying vegetable substances, and some are found upon living
plants, to which they are very injurious. To the naked eye they usually
appear as mouldy or cottony masses, either white, black, or coloured
blue, yellow, &c. The spores are attached singly or in rows to
branchlets arising from the ends of the filaments, so as to form little
heads.
_Bot´rytis parasit´ica_ (Pl. VII. fig. 19) is common upon the
flower-stalks of the Shepherd’s Purse, forming white mealy patches. The
fruit-stalks are comparatively large and thin-walled, the branchlets
being slender, mostly curved, and terminated each by a large, spherical,
smooth, simple, white spore.
_Botrytis vulgáris_ is also common on various decaying plants. Its
filaments are grey, and the branchlets lobe-like; the spores being
minute, spherical, either white or greenish, and placed simply at the
tips.
_Botrytis infes´tans_ is the potato-Fungus. It forms white spots upon
the under side of the leaves of the potato-plant, and by some authors is
considered to be the cause of the potato-disease. The filaments are
branched at the ends, and terminated by single oval spores, which are
apiculate at the free end, and contain minute little spores or sporidia.
_Oid´ium Tuck´eri_ is the well-known destructive grape-Fungus. It forms
white cottony masses upon the vine and its grapes, the fruit-stalks
being short and terminated by one or two end-to-end oblong spores. It
appears to be the Coniomycetous form of another Fungus (_Erysiphe_).
_Trichothécium róseum_ (Pl. VII. fig. 33) is found upon rotting sticks;
very frequently upon willow-baskets kept in a damp place. It forms
little rounded, slightly raised, pinkish spots, less than the size of a
pin’s head. The branched and septate foot-stalks (figs. 34, 35) are
terminated each by a little group of obovate spores, divided by a
transverse partition (uniseptate). Sometimes this little Fungus is quite
white, at others greenish; when perfectly ripe, the spores become
oblong.
_Penicil´lium glaúcum_ (Pl. VII. fig. 25) is the common Blue Mould found
upon decaying substances, as cheese, &c., the interwoven mycelial
filaments often forming large cakes or crusts upon the surface. The
septate fruit-stalks (fig. 26) are fork-branched at the ends, the
branchlets being terminated each by a row of very minute spherical
smooth spores. On some decaying substances, as apples, gum, &c., the
fruit-stalks are found aggregated into a thick stalk, the branchlets and
spores forming a rounded head, so that the whole resembles a little blue
mushroom (fig. 27). In this form the Fungus has been placed in a
distinct genus, and called _Corémium leúcopus_. In other species the
spores are pink and white.
This little Fungus is of special interest, on account of one form of it
constituting the yeast-plant, or yeast as it is commonly called. This
consists of rounded or oblong cells, which grow very rapidly in
fermenting liquids by budding--the large quantity of sugar and gluten
present favouring the vegetative or simple growing process, at the
expense of the fructifying process. But this is only an instance of what
we constantly find in flowering plants, the use of very rich soil
rendering flowers double, which is really reducing their organs to the
state of leaves. When the sugar has become exhausted, the cells of the
yeast become longer and thinner, as if starved; they then form a more
recognizable mycelium, which extends to the surface of the liquid, and
produces finally the fruit-stalks and the _Penicillium_ fruit. _
Aspergil´lus glaúcus_ (Pl. VIII. fig. 3) is an extremely common mould
upon cheese, jams, &c. It resembles the last in appearance to the naked
eye, except that it has rather a green tinge, the heads of fruit being
much more compact and rounded. The fruit-stalks (fig. 4) are large,
bulbous or inflated at the ends (fig. 5), and from the inflations arise
the crowded rows of spores. The spores are rounded, and rough (scabrous)
on the surface. On removing most of the spores from the head of fruit,
each row of spores is found to arise from a very short stalk.
Plate VII. fig. 21 represents a beautiful species of _Rhinot´richum_,
which is found upon decaying and sickly plants, and upon rotting sticks,
forming a minute grey mould. The fruit-stalks (fig. 22) are large,
sparingly branched, septate or jointed, appearing brownish under the
microscope. Their ends are branched, mostly biternate (fig. 23), _i. e._
each branch dividing into three branchlets, and these again into three
still finer ones. The ends of the branchlets are inflated, and coated
with little points, upon each of which a smooth white spore (fig. 24) is
placed.
ASCOMYCÉTES (ἁσκὀς, a bottle, μὑκης, fungus). The Fungi belonging to
this Order are found upon the stems and leaves of plants, and upon
decaying substances, as dung, &c. They are usually evident to the naked
eye, some even equalling the Hymenomycetous Fungi in size; and many of
them are brilliantly coloured. They are in general distinguishable with
facility from the Fungi of other Orders, by the arrangement of the
spores in colourless sacs or asci (Pl. VIII. fig. 9), resembling those
noticed in the case of the Lichens. These asci are usually enclosed in a
capsule or _perithécium_. The mycelium is usually buried in the matrix,
so as not to be conspicuous.
_Helvellácei._--To this family belongs the large genus _Pezíza_, some of
the species of which are beautifully coloured, yet scarcely microscopic.
Among these may be mentioned _Pezíza omphalódes_ (Pl. VIII. fig. 6),
which forms little red masses upon damp ceilings. It does not possess
the ordinary form of a _Peziza_, which is that of a cup fixed at the end
of a stalk, like a mushroom with the cup turned inside out, the asci
lining its interior.
_Peziza coccin´ea_ is not uncommon in woods. It is whitish outside, the
interior of the cup being of a brilliant scarlet colour. It is from half
an inch to an inch in height.
_Peziza stercor´ea_ (Pl. VIII. fig. 7) is often found upon dung. The
surface of the cup of this Fungus is granular and covered with bristles
(figs. 8 & 11). The cup is concave (fig. 10), and lined with the asci
(fig. 9), among which are simple paraphyses.
The _Pezizæ_ are excellent Ascomycetous Fungi for exhibiting the asci,
as they are more or less soft, and thus sections of them may be easily
prepared, or they may readily be picked to pieces with the mounted
needles.
TUBERACEI.--In this family is contained the Truffle (_Túber cibárium_).
The asci are situated upon the inner surfaces of the winding canals
traversing the substance of the fleshy fruit (_peridium_) of which the
truffle consists.
PHACIDIA´CEI.--To this family belongs _Hystérium frax´ini_ (Pl. VIII.
fig. 30), which is found upon ash-twigs. The drawn-out capsules or
perithecia (fig. 31) are black and elliptical, with a longitudinal
fissure or orifice, and contain the asci (fig. 32) with the spores.
SPHÆRIÁCEI.--_Dothid´ea typhína_ (Pl. VIII. fig. 12) is a common Fungus
upon the stems of living grasses. It forms an orange-coloured patch or
layer encircling the stem, and covered with little dots. On making a
section (fig. 14), it appears composed of a row of oblong or obovate
closely placed capsules (perithecia) immersed in and continuous with a
finely fibrous receptacular mass (_stróma_). The asci (fig. 15) are very
slender, arising in a tuft from the bottom of the capsules, and
containing eight still more slender spores. Except under a very high
power, the spores appear as interrupted lines running down the interior
of the asci. The little dots visible to the naked eye are the slightly
projecting mouths of the capsules, which are more distinctly seen in the
magnified portion of the Fungus (fig. 13). In the young state, this
Fungus is whitish.
This Fungus cannot be mistaken for a _Uredo_, two species of which occur
upon grasses--_Uredo lineáris_ forming yellowish-brown spots, and _Uredo
rubígo_ yellow spots.
_Dothidea ul´mi_ (Pl. VIII. fig. 24) forms black, slightly raised, and
somewhat star-shaped spots upon the upper surface of the leaves of the
elm. In a section (fig. 26) the cavities are seen, containing the very
delicate asci (fig. 25). The spores (fig. 27) are oval, with a minute
septum at one end.
_Sphæ´ria rubel´la_ (Pl. VIII. fig. 16) is extremely common on the dead
stems of the nettle, &c. In this Fungus the black bottle-like perithecia
(fig. 18), containing the asci and paraphyses (fig. 17), are at first
situated beneath the epidermis, through which they at length burst. The
spores (fig. 19 _a_) are spindle-shaped, and from four-to seven-septate.
When ripe, they escape by a hole or pore in the neck.
_Sphæ´ria complanáta_ (Pl. VIII. fig. 22) is another common species,
found in hedges, on dead sticks of the softer (herbaceous) plants, as
the parsley-order (Umbelliferæ). Here the minute capsules, which are
scattered over the stems, are at first rounded, then flattened on the
top (depressed), the neck being very minute (fig. 23). The spores in
this species are exceedingly minute, oblong, and not contained in asci.
_Sphæ´ria bulláta_ also belongs to this family. It occurs upon decaying
birch-sticks, presenting to the naked eye the appearance represented in
Pl. VIII. fig. 20. The black, raised tubercles (receptacles) in their
growth burst through the bark, splitting the epidermis. They consist of
a white stroma (fig. 20 _a_), in which the bottle-shaped capsules
(perithecia) are immersed, the necks projecting slightly above the
surface as little points (papillæ). The tufted spore-sacs or asci (fig.
21), with the thread-like paraphyses, are contained within the capsules;
and within the asci are the densely packed, very numerous and minute
curved spores.
Another species, _Sphæria discifor´mis_, is also common on birch-sticks.
It differs from the last in the tubercles being perfectly flat; the
spores are also longer, straight, and spindle-shaped (fusiform).
PERISPORÁCEI.--_Erys´iphe guttáta_ (Pl. VIII. fig. 33) is a member of
this family. It appears on the under side of the leaves of the common
hazel as a pale spot; and on closely examining it with the naked eye,
little black dots are seen scattered on the surface. These are the
capsules (conceptacles), which are seated upon straight white filaments.
The filaments (_fulcra_) are six or seven in number, and are placed
under the capsule, like the legs of a stool (fig. 34); they are rigid,
and swollen or inflated at the base (fig. 35). The asci are broad and
short, and contain only two spores.
_Erysiphe maculáris_ is the very destructive hop-mildew; and other
species are common on various plants.
_Chætómium elátum_ (Pl. VIII. fig. 29) resembles little tufts of brown
hairs, occurring upon decaying herbaceous stems. The capsule (fig. 28)
is crustaceous, and covered with interlaced, rough, branched hairs (fig.
28 _b_). The spores (fig. 28 _a_) are oval, with a little point at one
end (apiculate).
PHYSOMYCÉTES (φῦσα, bladder, μὑκης, fungus).--The Fungi belonging to
this order include some of the commonest moulds growing upon decaying
vegetable substances; while others are found upon leaves, &c. The flocci
are generally very evident; and the spores are contained in little
naked, bladder-like capsules (_peridíola_) at the ends of free
filaments.
MUCORINI.--In this family we have the common mould of paste, _Múcor
mucédo_ (Pl. VIII. fig. 36). It is easily recognized by the little
spherical capsules terminating the long and tufted fruit-stalks
(pedicels), which are perceptible to the naked eye. Each capsule
consists of a simple enlarged cell, the cavity of which is separated
from that of the stalk by a septum. They are white at first,
subsequently becoming brown and black. The minute crowded spores (fig.
36 _s_) are at first oblong, afterwards spherical. In the centre of the
capsule is a club-shaped body, or _columel´la_ (fig. 36 _a_), formed by
the elevation and inflation of the septum.
A beautiful little Fungus of this family, apparently referable to the
genus _Acrostalag´mus_ (Pl. VIII. fig. 37), is sometimes found upon soft
decaying stems. The main filaments are soft, smooth, and not septate.
The pedicels are very brittle, whorled, dichotomously branched,
scabrous, and terminated each by a little scabrous spherical vesicle
(fig. 37 _a_), containing two or three oblong spores.
ANTENNARIÉI.--In this family is _Racódium_ (or _Antennária_) _celláre_,
the Wine-cellar Fungus, forming the well-known cobweb-like masses
hanging from the walls, &c. The little black capsules are seated upon
slender septate filaments, and contain numerous round spores.
In examining leaves with the view of procuring Fungi, the reader will
most likely meet with the two kinds of bodies represented in Plate VIII.
figs. 38 & 39. These are not Fungi, but galls. They arise from an
abnormal growth of the leaf-structures, produced by the deposition of
the eggs of insects (_Cynipidæ_). The well-known oak-apple, and the red
hairy-looking body found upon hedge-roses, are both galls produced in
the same way.
_Examination and Preservation._--The examination of the Fungi scarcely
requires any special remarks. They should be viewed first as opake
objects under a low power; and then sections should be made, or the
textures separated with the mounted needles.
There is some difficulty in moistening the smaller filamentous Fungi
with water, which is requisite in the determination of the arrangement
of the spores upon the branches. Hence the best plan is to lay the
Fungus upon a slide, apply a cover, then to add a drop of spirit of wine
and afterwards a little water to the edge of the cover. When thus
wetted, the spores may be more or less removed with a wet hair-pencil,
when the ends of the branches will become perfectly distinct. In
examination of the dried smaller Fungi as the _Sphæriæ_, the capsules
should be macerated for a time in water.
The softer Fungi are very difficult of preservation in the entire state;
but the sections or minute structures may be mounted in chloride of
calcium or glycerine.
The harder and drier Fungi may be preserved by drying and gentle
pressure between coarse absorbent paper. They may then be glued to
pieces of paper and labelled, in the same manner as the flowering
plants. Specimens of the capsules, as of the _Sphæriæ_, &c., may also be
mounted in the dry state, the asci being preserved in the chloride of
calcium or glycerine, in which liquids most of the smaller Fungi will
keep extremely well.
PLATE IX. [PAGE 113.]
ANIMAL TISSUES, &c.
Fig.
1. Blood-corpuscles, Human.
2. Blood-corpuscles of Bird (Fowl).
3. Blood-corpuscles of Reptile (Frog).
4. Blood-corpuscles of Fish (Stickleback).
5. Hair of Bat.
6. Hair of Mouse.
7. Hair of Mouse.
8. Hair, human.
9. Hair, human.
10. Wool, fibre of.
11. Flax, fibres of.
12. Cotton, fibres of.
13. Silk, fibres of.
14. Feather, portion of: _a_, barbs; _b_, _c_, pinnæ.
15. Bone, section of: _a_, lacunæ.
16. Cartilage, section of.
17. Feather, downy.
18. Feather, downy: pinna.
19. Shell, pearly or nacreous portion of.
20. Muscle: _a_, cellular tissue; _b_, fibrillæ; _c_, bundle of
fibrillæ.
21. Tongue of Whelk: _a_, natural size.
22. Scale of Dace.
23. Scale of Perch.
24. Scale of Cod.
25. Spermatozoa of Chub.
26. _Flustra foliacea_: _a_, cells of; _b_, animal, with the tentacles
expanded.
27. _Flustra foliacea._
28. Shell of Oyster, brown portion of.
29. Shell of Oyster, prisms of.
30. _Cyclops quadricornis._
31. _Daphnia pulex_, female.
32. _Daphnia pulex_, head of male.
33. _Canthocamptus minutus_, an Entomostracan.
34. _Cypris tristriata._
35. _Cypris tristriata_, eggs of; 35 _a_, _b_, _c_, the same hatching.
36. _Acarus domesticus_ (Cheese-mite), female.
36*. Cilia of gills of Oyster.
37. _Trombidium fuliginosum_: _a_, pulp; _b_, mandible; _c_, foot; _d_,
natural size; _e_, hair; _f_, hair of _T. holosericeum_.
38. _Acarus domesticus_, male.
39. _Membranipora pilosa._
[Illustration: Plate IX.
W Bagg sculp
_London: John Van Voorst._]