known, in caves, and interesting accounts have been written of visits
to these subterranean mushroom-vaults of the gay city. In one of these
caves, at Montrouge, the proprietor gathers largely every day,
occasionally sending more than 400 pounds weight per day to market,
the average being about 300 pounds. There are six or seven miles' run
of mushroom-beds in this cave, and the owner is only one of a large
class who devote themselves to the culture of mushrooms. Large
quantities of preserved mushrooms are exported, one house sending to
England not less than 14,000 boxes in a year. Another cave near
Frépillon was in full force in 1867, sending as many as 3,000 pounds
of mushrooms to the Parisian markets daily. In 1867, M. Renaudot had
over twenty-one miles of mushroom-beds in one great cave at Méry, and
in 1869 there were sixteen miles of beds in a cave at Frépillon. The
temperature of these caves is so equal that the cultivation of the
mushroom is possible at all seasons of the year, but the best crops
are gathered in the winter.
Mr. Robinson gives an excellent account, not only of the subterranean,
but also of the open-air culture of mushrooms about Paris. The
open-air culture is never pursued in Paris during the summer, and
rarely so in this country.[D] What might be termed the domestic
cultivation of mushrooms is easy, that is, the growth by inexperienced
persons, for family consumption, of a bed of mushrooms in cellars,
wood-houses, old tubs, boxes, or other unconsidered places. Even in
towns and cities it is not impracticable, as horse-dung can always be
obtained from mews and stables. Certainly fungi are never so
harmless, or seldom so delicious, as when collected from the bed, and
cooked at once, before the slightest chemical change or deterioration
could possibly take place.
Mr. Cuthill's advice may be repeated here. He says:--"I must not
forget to remind the cottager that it would be a shilling or two a
week saved to him during the winter, if he had a good little bed of
mushrooms, even for his own family, to say nothing about a shilling or
two that he might gain by selling to his neighbours. I can assure him
mushrooms grow faster than pigs, and the mushrooms do not eat
anything; they only want a little attention. Addressing myself to the
working classes, I advise them, in the first place, to employ their
children or others collecting horse-droppings along the highway, and
if mixed with a little road-sand, so much the better. They must be
deposited in a heap during summer, and trodden firmly. They will heat
a little, but the harder they are pressed the less they will heat.
Over-heating must be guarded against; if the watch or trial stick
which is inserted into them gets too hot for the hand to bear, the
heat is too great, and will destroy the spawn. In that case artificial
spawn must be used when the bed is made up, but this expedient is to
be avoided on account of the expense. The easiest way for a cottager
to save his own spawn would be to do so when he destroys his old bed;
he will find all round the edges or driest parts of the dung one mass
of superior spawn; let him keep this carefully in a very dry place,
and when he makes up his next bed it can then be mixed with his summer
droppings, and will insure a continuance and excellent crop. These
little collections of horse-droppings and road-sand, if kept dry in
shed, hole, or corner, under cover, will in a short time generate
plenty of spawn, and will be ready to be spread on the surface of the
bed in early autumn, say by the middle of September or sooner. The
droppings during the winter must be put into a heap, and allowed to
heat gently, say up to eighty or ninety degrees; then they must be
turned over twice daily to let off the heat and steam; if this is
neglected the natural spawn of the droppings is destroyed. The
cottager should provide himself with a few barrowfuls of strawy dung
to form the foundation of his bed, so that the depth, when all is
finished, be not less than a foot. Let the temperature be up to milk
heat. He will then, when quite sure that the bed will not overheat,
put on his summer droppings. By this time these will be one mass of
natural spawn, having a grey mouldy and thready appearance, and a
smell like that of mushrooms. Let all be pressed very hard; then let
mould, unsifted, be put on, to the thickness of four inches, and
trodden down hard with the feet and watered all over; and the back of
a spade may now be used to make it still harder, as well as to plaster
the surface all over."[E] Mushrooms are cultivated very extensively by
Mr. Ingram, at Belvoir, without artificial spawn. There is a great
riding-house there, in which the litter is ground down by the horses'
feet into very small shreds. These are placed in a heap and turned
over once or twice during the season, when a large quantity of
excellent spawn is developed which, placed in asparagus beds or laid
under thin turf, produces admirable mushrooms, in the latter case as
clean as in our best pastures.[F]
Other species will sometimes be seen growing on mushroom-beds besides
the genuine mushroom, the spawn in such cases being probably
introduced with the materials employed. We have seen a pretty crisped
variety of _Agaricus dealbatus_ growing in profusion in such a place,
and devoured it accordingly. Sometimes the mushrooms will, when in an
unhealthy condition, be subject to the ravages of parasitic species of
mould, or perhaps of _Hypomyces_. _Xylaria vaporaria_ has, in more
than one instance, usurped the place of mushrooms. Mr. Berkeley has
received abundant specimens in the Sclerotioid state, which he
succeeded in developing in sand under a bell glass. Of course under
such conditions there is much loss. The little fairy-ring champignon
is an excellent and useful species, and it is a great pity that some
effort should not be made to procure it by cultivation. In Italy a
kind of _Polyporus_, unknown in this country, is obtained by watering
the _Pietra funghaia_, or fungus stone, a sort of tufa impregnated
with mycelium. The _Polypori_, it is said, take seven days to come to
perfection, and may be obtained from the foster mass, if properly
moistened, six times a year. There are specimens which were fully
developed in Mr. Lee's nursery at Kensington many years since. Another
fungus is obtained from the pollard head of the black poplar. Dr.
Badham says that it is usual to remove these heads at the latter end
of autumn, as soon as the vintage is over, and their marriage with the
vine is annulled; hundreds of such heads are then cut and transported
to different parts; they are abundantly watered during the first
month, and in a short time produce that truly delicious fungus
_Agaricus caudicinus_, which, during the autumn of the year, makes the
greatest show in the Italian market-places. These pollard blocks
continue to bear for from twelve to fourteen years.
Another fungus, which Dr. Badham himself reared (_Polyporus
avellanus_), is procured by singeing, over a handful of straw, a block
of the cob-nut tree, which is then watered and put by. In about a
month the fungi make their appearance, and are quite white, of from
two to three inches in diameter, and excellent to eat, while their
profusion is sometimes so great as entirely to hide the wood from
whence they spring.[G] It has been said that _Boletus edulis_ may be
propagated by watering the ground with a watery infusion of the
plants, but we have no knowledge of this method having been pursued
with success.
The culture of truffles has been partially attempted, on the principle
that, in some occult manner, certain trees produced truffles beneath
their shade. It is true that truffles are found under trees of special
kinds, for Mr. Broome remarks that some trees appear more favourable
to the production of truffles than others. Oak and hornbeam are
specially mentioned; but, besides these, chestnut, birch, box, and
hazel are alluded to. He generally found _Tuber oestivum_ under
beech-trees, but also under hazel, _Tuber macrosporum_ under oaks, and
_Tuber brumale_ under oaks and abele. The men who collect truffles
for Covent Garden Market obtain them chiefly under beech, and in mixed
plantations of fir and beech.[H]
Some notion may be obtained of the extent to which the trade of
truffles is carried in France, when we learn that in the market of Apt
alone about 3,500 pounds of truffles are exposed for sale every week
during the height of the season, and the quantity sold during the
winter reaches upwards of 60,000 pounds, whilst the Department of
Vaucluse yields annually upwards of 60,000 pounds. It may be
interesting here to state that the value of truffles is so great in
Italy that precautions are taken against truffle poachers, much in the
same way as against game poachers in England. They train their dogs so
skilfully that, while they stand on the outside of the truffle
grounds, the dogs go in and dig for the fungi. Though there are
multitudes of species, they bring out those only which are of market
value. Some dogs, however, are employed by botanists, which will hunt
for any especial species that may be shown to them. The great
difficulty is to prevent them devouring the truffles, of which they
are very fond. The best dogs, indeed, are true retrievers.
The Count de Borch and M. de Bornholz give the chief accounts of the
efforts that have been made towards the cultivation of these fungi.
They state that a compost is prepared of pure mould and vegetable soil
mixed with dry leaves and sawdust, in which, when properly moistened,
mature truffles are placed in winter, either whole or in fragments,
and that after the lapse of some time small truffles are found in the
compost.[I] The most successful plan consists in sowing acorns over a
considerable extent of land of a calcareous nature; and when the young
oaks have attained the age of ten or twelve years, truffles are found
in the intervals between the trees. This process was carried on in the
neighbourhood of Loudun, where truffle-beds had formerly existed, but
where they had long ceased to be productive--a fact indicating the
aptitude of the soil for the purpose. In this case no attempt was
made to produce truffles by placing ripe specimens in the earth, but
they sprang up themselves from spores probably contained in the soil.
The young trees were left rather wide apart, and were cut, for the
first time, about the twelfth year after sowing, and afterwards at
intervals of from seven to nine years. Truffles were thus obtained for
a period of from twenty-five to thirty years, after which the
plantations ceased to be productive, owing, it was said, to the ground
being too much shaded by the branches of the young trees. It is the
opinion of the Messrs. Tulasne that the regular cultivation of the
truffle in gardens can never be so successful as this so-called
indirect culture at Loudun, but they think that a satisfactory result
might be obtained in suitable soils by planting fragments of mature
truffles in wooded localities, taking care that the other conditions
of the spots selected should be analogous to those of the regular
truffle-grounds, and they recommend a judicious thinning of the trees
and clearing the surface from brushwood, etc., which prevents at once
the beneficial effects of rain and of the direct sun's rays. A truffle
collector stated to Mr. Broome that whenever a plantation of beech, or
beech and fir, is made on the chalk districts of Salisbury Plain,
after the lapse of a few years truffles are produced, and that these
plantations continue productive for a period of from ten to fifteen
years, after which they cease to be so.
M. Gasparin reported to the jurors of the Paris Exhibition of 1855,
concerning the operations of M. Rousseau, of Carpentras, on the
production of oak truffles in France. The acorns of evergreen and of
common oaks were sown about five yards apart. In the fourth year of
the plantation three truffles were found; at the date of the report
the trees were nine years old, and over a yard in height. Sows were
employed to search for the truffles. Although these plantations
consist both of the evergreen and common oak, truffles cannot be
gathered at the base of the latter species, it so happening that it
arrives later at a state of production. The common oak, however,
produces truffles like the evergreen oak, this report states, for a
great number of the natural truffle-grounds at Vaucluse are planted
with common oaks. It is remarked that the truffles produced from
these are larger but less regular than those of the evergreen oak,
which are smaller, but nearly always spherical. The truffles are
gathered at two periods of the year; in May only white truffles are to
be found, which never blacken and have no odour; they are dried and
sold for seasoning. The black truffles (_Tuber melanosporum_) commence
forming in June, enlarging towards the frosty season; then they become
hard, and acquire all their perfume. They are dug a month before and a
month after Christmas. It is also asserted that truffles are produced
about the vine, or at any rate that the association of the vine is
favourable to the production of truffles, because truffle-plots near
vines are very productive. The observation of this decided M. Rousseau
to plant a row of vines between the oaks. The result of this
experiment altogether does not appear to have been by any means
flattering, for at the end of eight years only little more than
fifteen pounds were obtained from a hectare of land, which, if valued
at 45 francs, would leave very little profit. M. Rousseau also called
attention to a meadow manured (_sic_) with parings of truffles, which
was said to have given prodigious results.
The cultivation of minute fungi for scientific purposes has been
incidentally alluded to and illustrated in foregoing chapters, and
consequently will not require such full and particular details
here. Somewhat intermediately, we might allude to the species of
_Sclerotium_, which are usually compact, externally blackish,
rounded or amorphous bodies, consisting of a cellular mass of the
nature of a concentrated mycelium. Placed in favourable conditions,
these forms of _Sclerotium_ will develop the peculiar species of
fungus belonging to them, but in certain cases the production is more
rapid and easy than in others. In this country, Mr. F. Currey has
been the most successful in the cultivation of _Sclerotia_. The
method adopted is to keep them in a moist, somewhat warm, but
equable atmosphere, and with patience await the results. The
well-known ergot of rye, wheat, and other grasses may be so
cultivated, and Mr. Currey has developed the ergot of the common
reed by keeping the stem immersed in water. The final conditions
are small clavate bodies of the order _Sphæriacei_, belonging to
the genus _Claviceps_. The _Sclerotium_ of the _Eleocharis_ has been
found in this country, but we are not aware that the _Claviceps_
developed from it has been met with or induced by cultivation. One
method recommended for this sort of experiment is to fill a
garden-pot half full of crocks, over which to place sphagnum broken
up until the pot is nearly full, on this to place the _Sclerotia_,
and cover with silver sand; if the pot is kept standing in a pan of
water in a warm room, it is stated that production will ensue.
Ergot of the grasses will not always develop under these conditions,
but perseverance may ultimately ensure success.
A species of _Sclerotium_ on the gills of dead Agarics originates
_Agaricus tuberosus_, another _Agaricus cirrhatus_,[J] but this should
be kept _in situ_ when cultivated artificially, and induced to develop
whilst still attached to the rotten Agarics. _Peziza tuberosa_, in
like manner, is developed from _Sclerotia_, usually found buried in
the ground in company with the roots of _Anemone nemorosa_. At one
time it was supposed that some relationship existed between the roots
of the anemone and the _Sclerotia_. From another _Sclerotium_, found
in the stems of bulrushes, Mr. Currey has developed a species of
_Peziza_, which has been named _P. Curreyana_.[K] This _Peziza_ has
been found growing naturally from the _Sclerotia_ imbedded in the
tissue of common rushes. De Bary has recorded the development of
_Peziza Fuckeliana_ from a _Sclerotium_ of which the conidia take the
form of a species of _Polyactis_. _Peziza ciborioides_ is developed
from a _Sclerotium_ found amongst dead leaves; and recently we have
received from the United States an allied _Peziza_ which originated
from the _Sclerotia_ found on the petals of _Magnolia_, and which has
been named _Peziza gracilipes_, Cooke, from its very slender,
thread-like stem. Other species of _Peziza_ are also known to be
developed from similar bases, and these Fuckel has associated
together under a proposed new genus with the name of _Sclerotinia_.
Two or three species of _Typhula_, in like manner, spring from forms
of _Sclerotium_, long known as _Sclerotium complanatum_ and
_Sclerotium scutellatum_. Other forms of _Sclerotium_ are known, from
one of which, found in a mushroom-bed, Mr. Currey developed _Xylaria
vaporaria_, B., by placing it on damp sand covered with a bell
glass.[L] Others, again, are only known in the sclerotioid state, such
as the _Sclerotium stipitatum_ found in the nests of white ants in
South India.[M] From what is already known, however, we feel justified
in the conclusion that the so-called species of _Sclerotium_ are a
sort of compact mycelium, from which, under favourable conditions,
perfect fungi may be developed. Mr. Berkeley succeeded in raising from
the minute _Sclerotium_ of onions, which looks like grains of coarse
gunpowder, a species of _Mucor_. This was accomplished by placing a
thin slice of the _Sclerotium_ in a drop of water under a glass slide,
surrounded by a pellicle of air, and luted to prevent evaporation and
external influences.[N]
As to the cultivation of moulds and _Mucors_, one great difficulty has
to be encountered in the presence or introduction of foreign spores to
the matrix employed for their development. Bearing this in mind,
extensive cultivations may be made, but the conditions must influence
the decision upon the results. Rice paste has been used with advantage
for sowing the spores of moulds, afterwards keeping them covered from
external influences. In cultivation on rice paste of rare species, the
experimenter is often perplexed by the more rapid growth of the common
species of _Mucor_ and _Penicillium_. Mr. Berkeley succeeded in
developing up to a certain point the fungus of the Madura Foot, but
though perfect sporangia were produced, the further development was
masked by the outgrowth of other species. In like manner, orange
juice, cut surfaces of fruits, slices of potato tubers, etc., have
been employed. Fresh, horse-dung, placed under a bell glass and kept
in a humid atmosphere, will soon be covered with _Mucor_, and in like
manner the growth of common moulds upon decayed fruit may be watched;
but this can hardly be termed cultivation unless the spores of some
individual species are sown. Different solutions have been proposed
for the growth of such conditions as the cells which induce
fermentation, to which yeast plants belong. A fly attacked by _Empusa
muscæ_, if immersed in water, will develop one of the _Saprolegniæ_.
The _Uredines_ and other epiphyllous _Coniomycetes_ will readily
germinate by placing the leaf which bears them on damp sand, or
keeping them in a humid atmosphere. Messrs. Tulasne and De Bary have,
in their numerous memoirs, detailed the methods adopted by them
for different species, both for germination of the pseudospores and
for impregnating healthy foster plants. The germination of the
pseudospores of the species of _Podisoma_ may easily be induced, and
secondary fruits obtained. The germination of the spores of _Tilletia_
is more difficult to accomplish, but this may be achieved. Mr.
Berkeley found no difficulty, and had the stem impregnated as well as
the germen. On the other hand, the pseudospores of _Cystopus_,
when sown in water on a slip of glass, will soon produce the
curious little zoospores in the manner already described.
The sporidia of the _Discomycetes_, and some of the _Sphæriacei_,
germinate readily in a drop of water on a slip of glass, although not
proceeding further than the protrusion of germ-tubes. A form of slide
has been devised for growing purposes, in which the large covering
glass is held in position, and one end of the slip being kept immersed
in a vessel of water, capillary attraction keeps up the supply for an
indefinite period, so that there is no fear of a check from the
evaporation of the fluid. Even when saccharine solutions are employed
this method may be adopted.
The special cultivation of the _Peronosporei_ occupied the attention
of Professor De Bary for a long time, and his experiences are
detailed in his memoir on that group,[O] but which are too long
for quotation here, except his observations on the development of the
threads of _Peronospora infestans_ on the cut surface of the tubers
of diseased potatoes. When a diseased potato is cut and sheltered from
dessication, the surface of the slice covers itself with the mycelium
and conidiiferous branches of _Peronospora_, and it can easily be
proved that these organs originate from the intercellulary tubes of
the brown tissue. The mycelium that is developed upon these slices
is ordinarily very vigorous; it often constitutes a cottony mass of a
thickness of many millimetres, and it gives out conidiiferous
branches, often partitioned, and larger and more branched than those
observed on the leaves. The appearance of these fertile branches
ordinarily takes place at the end of from twenty-four to forty-eight
hours; sometimes, nevertheless, one must wait for many days. These
phenomena are observed in all the diseased tubercles without
exception, so long as they have not succumbed to putrefaction,
which arrests the development of the parasite and kills it.
Young plants of the species liable to attack may be inoculated with
the conidia of the species of _Peronospora_ usually developed on that
particular host, in the same manner that young cruciferous plants,
watered with an infusion of the spores of _Cystopus candidus_, will
soon exhibit evidence of attack from the white rust.
It is to the cultivation and close investigation of the growth and
metamorphoses of the minute fungi that we must look for the most
important additions which have yet to be made to our knowledge of the
life-history of these most complex and interesting organisms.
[A] Experiments were made at Belvoir, by Mr. Ingram, in the
cultivation of several species of _Agaricini_, but without
success, and a similar fate attended some spawn of a very
superior kind from the Swan River, which was submitted to the
late Mr. J. Henderson. No result was obtained at Chiswick,
either from the cultivation of truffles or from the inoculation
of grass-plots with excellent spawn. Mr. Disney's experiments
at the Hyde, near Ingatestone, were made with dried truffles,
and were not likely to succeed. The Viscomte Nôe succeeded in
obtaining abundant truffles, in an enclosed portion of a wood
fenced from wild boars, by watering the ground with an infusion
of fresh specimens; but it is possible that as this took place
in a truffle country, there might have been a crop without any
manipulation. Similar trials, and it is said successfully, have
been made with _Boletus edulis_. Specimens of prepared
truffle-spawn were sent many years since to the "Gardener's
Chronicle," but they proved useless, if indeed they really
contained any reliable spawn.
[B] Robinson, "On Mushroom Culture," London, 1870. Cuthill, "On the
Cultivation of the Mushroom," 1861. Abercrombie, "The Garden
Mushroom; its Culture, &c." 1802.
[C] This has, however, not been confirmed, and is considered (how
justly we cannot say) a "canard."
[D] This method is pursued with great success by Mr. Ingram, at
Belvoir, and by Mr. Gilbert, at Burleigh.
[E] Cuthill, "Treatise on the Cultivation of the Mushroom," p. 9.
[F] Mr. Berkeley lately recommended, at one of the meetings of the
Horticultural Society at South Kensington, that the railway
arches should be utilized for the cultivation of mushrooms.
[G] Badham, "Esculent Funguses," 1st ed. p. 43.
[H] Broome, "On Truffle Culture," in "Journ. Hort. Soc." i. p. 15
(1866).
[I] No faith, however, is, in general, placed on these treatises, as
they were merely conjectural.