Chapter M: J. Berkeley (10)

Mr. Phillips has recently indicated the species of fungi found by him on charcoal beds in Shropshire,[H] but, useful as it is, that only refers to one locality. A complete list of all the fungi which have been found growing on charcoal beds, burnt soil, or charred wood, would be rather extensive. The fungi found in hothouses and stoves are also numerous, and often of considerable interest from the fact that they have many of them never been found elsewhere. Those found in Britain,[I] for instance, are excluded from the British Flora as doubtful, because, growing upon or with exotic plants, they are deemed to be of exotic origin, yet in very few cases are they known to be inhabitants of any foreign country. Some species found in such localities are not confined to them, as _Agaricus coepestipes_, _Agaricus cristatus_, _Æthalium vaporarium_, &c. It is somewhat singular that certain species have a predilection for growing in proximity with other plants with which they do not appear to have any more intimate relation. Truffles, for instance, in association with oaks, _Peziza lanuginosa_ under cedar-trees, _Hydnangium carneum_ about the roots of _Eucalypti_, and numerous species of _Agaricini_, which are only found under trees of a particular kind. As might be anticipated, there is no more fertile habitat for fungi than the dung of animals, and yet the kinds found in such locations belong to but a few groups. Amongst the _Discomycetes_, a limited number of the genus _Peziza_ are fimicolous, but the allied genus _Ascobolus_, and its own immediate allies, include amongst its species a large majority that are found on dung. If we take the number of species at sixty-four, there are only seven or eight which do not occur on dung, whilst fifty-six are fimicolous. The species of _Sphæria_ which are found on the same substances are also closely allied, and some Continental authors have grouped them under the two proposed genera _Sporormia_ and _Sordaria_, whilst Fuckel[J] proposes a distinct group of _Sphæriacei_, under the name of _Fimicoli_, in which he includes as genera _Coprolepa_, _Hypocopra_, _Delitschia_, _Sporormia_, _Pleophragmia_, _Malinvernia_, _Sordaria_, and _Cercophora_. The two species of _Pilobolus_, and some of _Mucor_, are also found on dung, _Isaria felina_ on that of cats, _Stilbum fimetarium_ and a few other moulds, and amongst Agarics some species of _Coprinus_. Animal substances are not, as a rule, prolific in the production of fungi. _Ascobolus saccharinus_ and one or two others have been found upon old leather. _Onygena_ of two or three species occurs on old horn, hoofs, &c. Cheese, milk, &c., afford a few forms, but the largest number infest dead insects, either under the mouldy form of _Isaria_ or the more perfect condition of _Torrubia_, and occasionally under other forms.

Robin[K] has recorded that three species of _Brachinus_, of the order Coleoptera, have been found infected, whilst living, with a minute yellow fungus which he calls _Laboulbenia Rougeti_, and the same species has been noted on other beetles. _Torrubia Melolonthæ_[L] has been described by Tulasne as occurring on the maybug or cockchafer, which is allied to, if not identical with, _Cordyceps Ravenelii_, B. and C., and also that described and figured by M. Fougeroux de Bondaroy.[M] _Torrubia curculionum_, Tul., occurs on several species of beetles, and seems to be by no means uncommon in Brazil and Central America. _Torrubia coespitosa_, Tul., which may be the same as _Cordyceps Sinclairi_, B.,[N] is found on the larvæ of _Orthoptera_ in New Zealand, _Torrubia Miquelii_ on the larvæ of _Cicada_ in Brazil, and _Torrubia sobolifera_ on the pupæ of _Cicada_ in the West Indies. A romantic account is given of this in an extract cited by Dr. Watson in his communication to the Royal Society.[O] "The vegetable fly is found in the island Dominica, and (excepting that it has no wings) resembles the drone, both in size and colour, more than any other English insect. In the month of May it buries itself in the earth and begins to vegetate. By the latter end of July, the tree is arrived at its full growth, and resembles a coral branch, and is about three inches high, and bears several little pods, which, dropping off, become worms, and from thence flies, like the English caterpillar." _Torrubia Taylori_, which grows from the caterpillar of a large moth in Australia, is one of the finest examples of the genus. _Torrubia Robertsii_, from New Zealand, has long been known as attacking the larva of _Hepialus virescens_. There are several other species on larvæ of different insects, on spiders, ants, wasps, &c., and one or two on mature Lepidoptera, but the latter seem to be rare.

That fungi should make their appearance and flourish in localities and conditions generally considered inimical to vegetable life is no less strange than true. We have already alluded to the occurrence of some species on spent tan, and some others have been found in locations as strange. We have seen a yellow mould resembling _Sporotrichum_ in the heart of a ball of opium, also a white mould appears on the same substance, and more than one species is troublesome in the opium factories of India. A mould made its appearance some years since in a copper solution employed for electrotyping in the Survey Department of the United States,[P] decomposing the salt, and precipitating the copper. Other organisms have appeared from time to time in various inorganic solutions, some of which were considered destructive to vegetable life, and it is not improbable that some of these organisms were low conditions of mould. It may well occasion some surprise that fungi should be found growing within cavities wholly excluded from the external air, as in the hollow of filberts, and the harder shelled nuts of _Guilandina_, in the cavities of the fruit of tomato, or in the interior of an egg. It is scarcely less extraordinary that _Hypocrea inclusa_ should flourish in the interior of a kind of truffle.

From the above it will be concluded that the habitats of fungi are exceedingly variable, that they may be regarded as almost universal wherever decaying vegetable matter is found, and that under some conditions animal substances, especially of vegetable feeders, such as insects, furnish a pabulum for their development.

A very curious and interesting inquiry presents itself to our minds, which is intimately related to this subject of the habitats of fungi. It shapes itself into a sort of "puzzle for the curious," but at the same time one not unprofitable to think about. How is the occurrence of new and before unknown forms to be accounted for in a case like the following?[Q]

It was our fortune--good fortune as far as this investigation was concerned--to have a portion of wall in our dwelling persistently damp for some months. It was close to a cistern which had become leaky. The wall was papered with "marbled" paper, and varnished. At first there was for some time nothing worthy of observation, except a damp wall--decidedly damp, discoloured, but not by any means mouldy. At length, and rather suddenly, patches of mould, sometimes two or three inches in diameter, made their appearance. These were at first of a snowy whiteness, cottony and dense, just like large tufts of cotton wool, of considerable expansion, but of miniature elevation. They projected from the paper scarcely a quarter of an inch. In the course of a few weeks the colour of the tufts became less pure, tinged with an ochraceous hue, and resembling wool rather than cotton, less beautiful to the naked eye, or under a lens, and more entangled. Soon after this darker patches made their appearance, smaller, dark olive, and mixed with, or close to, the woolly tufts; and ultimately similar spots of a dendritic character either succeeded the olive patches, or were independently formed. Finally, little black balls, like small pin heads, or grains of gunpowder, were found scattered about the damp spots. All this mouldy forest was more than six months under constant observation, and during that period was held sacred from the disturbing influences of the housemaid's broom and duster.

Curiosity prompted us from the first to submit the mouldy denizens of the wall to the microscope, and this curiosity was increased week by week, on finding that none of the forms found vegetating on nearly two square yards of damp wall could be recognized as agreeing specifically with any described moulds with which we were acquainted. Here was a problem to be solved under the most favourable conditions, a forest of mould indoors, within a few yards of the fireside, growing quite naturally, and all strangers. Whence could these new forms proceed?

The cottony tufts of white mould, which were the first to appear, had an abundant mycelium, but the erect threads which sprang from this were for a long time sterile, and closely interlaced. At length fertile threads were developed in tufts, mixed with the sterile threads. These fruit-bearers were shorter and stouter, more sparingly branched, but beset throughout nearly their whole length with short patent, alternate branchlets. These latter were broadest towards the apex, so as to be almost clavate, and the extremity was beset with two or three short spicules. Each spicule was normally surmounted by an obovate spore. The presence of fertile threads imparted the ochraceous tint above alluded to. This tint was slight, and perhaps would not have been noticed, but from the close proximity of the snow-white tufts of barren threads. The fertile flocci were decumbent, probably from the weight of the spores, and the tufts were a little elevated above the surface of the matrix. This mould belonged clearly to the _Mucedines_, but it hardly accorded well with any known genus, although most intimately related to _Rhinotrichum_, in which it was placed as _Rhinotrichum lanosum_.[R]

The white mould having become established for a week or two, small blackish spots made their appearance on the paper, sometimes amongst thin patches of the mould, and sometimes outside them. These spots, at first cloudy and indefinite, varied in size, but were usually less than a quarter of an inch in diameter. The varnish of the paper was afterwards pushed off in little translucent flakes or scales, an erect olivaceous mould appeared, and the patches extended to nearly an inch in diameter, maintaining an almost universal circular form. This new mould sometimes possessed a dirty reddish tint, but was commonly dark olive. There could be no mistake about the genus to which this mould belonged; it had all the essential characters of _Penicillium_. Erect jointed threads, branched in the upper portion in a fasciculate manner, and bearing long beaded threads of spores, which formed a tassel-like head, at the apex of each fertile thread. Although at first reminded of _Penicillium olivaceum_, of Corda, by the colour of this species, it was found to differ in the spores being oblong instead of globose, and the ramifications of the flocci were different. Unable again to find a described species of _Penicillium_ with which this new mould would agree, it was described under the name of _Penicillium chartarum_.[S]

Almost simultaneously, or but shortly after the perfection of the spores of _Penicillium_, other and very similar patches appeared, distinguished by the naked eye more particularly by their dendritic form. This peculiarity seemed to result from the dwarfed habit of the third fungus, since the varnish, though cracked and raised, was not cast off, but remained in small angular fragments, giving to the spots their dendritic appearance, the dark spores of the fungus protruding through the fissures. This same mould was also found in many cases growing in the same spots amongst _Penicillium chartarum_, but whether from the same mycelium could not be determined.

The distinguishing features of this fungus consist in an extensive mycelium of delicate threads, from which arise numerous erect branches, bearing at the apex dark brown opaque spores. Sometimes the branches were again shortly branched, but in the majority of instances were single. The septate spores had from two to four divisions, many of them divided again by cross septa in the longitudinal direction of the spore, so as to impart a muriform appearance. As far as the structure and appearance of the spores are concerned, they resembled those of _Sporidesmium polymorphum_, under which name specimens were at first published,[T] but this determination was not satisfactory. The mycelium and erect threads are much too highly developed for a good species of _Sporidesmium_, although the name of _Sporidesmium alternaria_ was afterwards adopted. In fresh specimens of this fungus, when seen _in situ_ by a half-inch objective, the spores appear to be moniliform, but if so, all attempts to see them so connected, when separated from the matrix, failed. On one occasion, a very immature condition was examined, containing simple beaded, hyaline bodies, attached to each other by a short neck. The same appearance of beaded spores, when seen _in situ_, was recognized by a mycological friend, to whom specimens were submitted for confirmation.[U]

The last production which made its appearance on our wall-paper burst through the varnish as little black spheres, like grains of gunpowder. At first the varnish was elevated by pressure from beneath, then the film was broken, and the little blackish spheres appeared. These were, in the majority of cases, gregarious, but occasionally a few of the spheres appeared singly, or only two or three together. As the whole surface of the damp paper was covered by these different fungi, it was scarcely possible to regard any of them as isolated, or to declare that one was not connected with the mycelium of the others. The little spheres, when the paper was torn from the wall, were also growing from the under surface, flattened considerably by the pressure. The spherical bodies, or perithecia, were seated on a plentiful hyaline mycelium. The walls of the perithecia, rather more carbonaceous than membranaceous, are reticulated, reminding one of the conceptacles of _Erysiphe_, to which the perithecia bear considerable resemblance. The ostiolum is so obscure that we doubt its existence, and hence the closer affinity of the plant to the _Perisporiacei_ than to the _Sphæriacei_. The interior of the perithecium is occupied by a gelatinous nucleus, consisting of elongated cylindrical asci, each enclosing eight globose hyaline sporidia, with slender branched paraphyses. A new genus has been proposed for this and another similar form, and the present species bears the name of _Orbicula cyclospora_.[V]

The most singular circumstance connected with this narrative is the presence together of four distinctly different species of fungi, all of them previously unknown and undescribed, and no trace amongst them of the presence of any one of the very common species, which would be supposed to develop themselves under such circumstances. It is not at all unusual for _Sporocybe alternata_, B., to appear in broad black patches on damp papered walls, but in this instance not a trace was to be found. What were the peculiar conditions present in this instance which led to the manifestation of four new forms, and none of the old ones? We confess that we are unable to account satisfactorily for the mystery, but, at the same time, feel equally unwilling to invent hypotheses in order to conceal our own ignorance.

[A] These predilections must be accepted as general, to which there
will be exceptions.

[B] Viviani, "I Funghi d'Italia."

[C] Badham's "Esculent Funguses," Ed. i. pp. 42, 116.

[D] An excellent white Agaric occurs on ant nests in the
Neilgherries, and a curious species is found in a similar
position in Ceylon.

[E] Westendorp, "Les Cryptogams après leurs stations naturelles."

[F] Cooke, "On Nettle Stems and their Micro-Fungi," in "Journ.
Quekett Micro. Club," iii. p. 69.

[G] Westendorp, "Les Cryptogams après leurs stations naturelles,"
1865.

[H] "Gardener's Chronicle," 1874.

[I] W. G. Smith, in "Journ. Botany," March, 1873; Berkeley, in
"Grevillea," vol. i. p. 88.

[J] Fuckel, "Symbolæ Mycologicæ," p. 240.

[K] Robin, "Végét. Parasites," p. 622, t. viii. f. 1, 2.

[L] Tulasne, "Selecta Fung. Carp." iii. p. 12.

[M] "Hist. de l'Acad. des Sciences," 1769. Paris, 1772.

[N] Berkeley, "Crypt. Bot." p. 73; Hooker, "New Zealand Flora," ii.
338.

[O] "Philosophical Transactions," liii. (1763), p. 271.

[P] Berkeley's "Outlines," p. 30.

[Q] "Popular Science Review," vol. x. (1871), p. 25.

[R] Specimens of this mould were distributed in Cooke's "Fungi
Britannici Exsiccati," No. 356, under the name of _Clinotrichum
lanosum_.

[S] Cooke's "Handbook of British Fungi," p. 602.

[T] Cooke's "Fungi Britannici Exsiccati," No. 329, under the name of
_Sporidesmium polymorphum_ var. _chartarum_.

[U] This reminds one of Preuss's _Alternaria_, figured in Sturm's
"Flora;" it has been suggested that the mould, as seen when
examined under a power of 320 diam., is very much like a
_Macrosporium_. Again arises the question of the strings of
spores attached end to end.

[V] "Handbook of British Fungi," vol. ii. p. 926, No. 2,788.

XII.

CULTIVATION.

The cultivation of fungi in this country for esculent purposes is confined to a single species, and yet there is no reason why, by a series of well-conducted experiments, means should not be devised for the cultivation of others, for instance, _Marasmius orcades_, and the morel. Efforts have been made on the Continent for the cultivation of truffles, but the success has hitherto been somewhat doubtful. For the growth of the common mushroom, very little trouble and care is required, and moderate success is certain. A friend of ours some years since was fortunate enough to have one or two specimens of the large puff-ball, _Lycoperdon giganteum_, growing in his garden. Knowing its value, and being particularly fond of it when fried for breakfast, he was anxious to secure its permanence. The spot on which the specimens appeared was marked off and guarded, so that it was never desecrated by the spade, and the soil remained consequently undisturbed. Year after year, so long as he resided on the premises, he counted upon and gathered several specimens of the puff-ball, the mycelium continuing to produce them year after year. All parings, fragments, &c., not utilized of the specimens eaten were cast on this spot to rot, so that some of the elements might be returned to the soil. This was not true cultivation perhaps, as the fungus had first established itself, but it was preservation, and had its reward. It must be admitted, however, that the size and number of specimens diminished gradually, probably from exhaustion of the soil. This fungus, though strong, is much approved by many palates, and its cultivation might be attempted. Burying a ripe specimen in similar soil, and watering ground with the spores, has been tried without success.[A]

As to the methods adopted for cultivation of the common mushroom, it is unnecessary to detail them here, as there are several special treatises devoted to the subject, in which the particulars are more fully given than the limits of this chapter will permit.[B] Recently, M. Chevreul exhibited at the French Academy some splendid mushrooms, said to have been produced by the following method: he first develops the mushrooms by sowing spores on a pane of glass, covered with wet sand; then he selects the most vigorous individuals from among them, and sows, or plants their mycelium in a cellar in a damp soil, consisting of gardener's mould, covered with a layer of sand and gravel two inches thick, and another layer of rubbish from demolitions, about an inch deep. The bed is watered with a diluted solution of nitrate of potash, and in about six days the mushrooms grow to an enormous size.[C] The cultivation of mushrooms for the market, even in this country, is so profitable, that curious revelations sometimes crop up, as at a recent trial at the Sheriffs' Court for compensation by the Metropolitan Railway Company for premises and business of a nurseryman at Kensington. The Railway had taken possession of a mushroom-ground, and the claim for compensation was £716. It was stated in evidence that the profits on mushrooms amounted to 100 or 150 per cent. One witness said if £50 were expended, in twelve months, or perhaps in six months, the sum realized would be £200.

Immense quantities of mushrooms are produced in Paris, as is well 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.

[J] Dr. Bull has been very successful in developing the _Sclerotium_
of _Agaricus cirrhatus_.

[K] Currey, "On Development of _Sclerotium roseum_," in "Journ. Linn.
Soc." vol. i. p. 148.

[L] Currey, in "Linn. Trans." xxiv. pl. 25, figs. 17, 26.

[M] Berkeley, "On Two Tuberiform Veg. Productions from Travancore,"
in "Trans. Linn. Soc." vol. xxiii. p. 91.

[N] Berkeley, "On a Peculiar Form of Mildew in Onions," "Journ. Hort.
Soc." vol. iii p. 91.

[O] De Bary, "Ann. des Sci. Nat." 4th series, vol. xx.

XIII.

GEOGRAPHICAL DISTRIBUTION.

Unfortunately no complete or satisfactory account can be given of the geographical distribution of fungi. The younger Fries,[A] with all the facilities at his disposal which the lengthened experience and large collections of his father afforded, could only give a very imperfect outline, and now we can add very little to what he has given. The cause of this difficulty lies in the fact that the Mycologic Flora of so large a portion of the world remains unexplored, not only in remote regions, but even in civilized countries where the Phanerogamic Flora is well known. Europe, England, Scotland, and Wales are as well explored as any other country, but Ireland is comparatively unknown, no complete collection having ever been made, or any at least published. Scandinavia has also been well examined, and the northern portions of France, with Belgium, some parts of Germany and Austria, in Russia the neighbourhood of St. Petersburg, and parts of Italy and Switzerland. Turkey in Europe, nearly all Russia, Spain, and Portugal are almost unknown. As to North America, considerable advances have been made since Schweinitz by Messrs. Curtis and Ravenel, but their collections in Carolina cannot be supposed to represent the whole of the United States; the small collections made in Texas, Mexico, etc., only serve to show the richness of the country, not yet half exhausted. It is to be hoped that the young race of botanists in the United States will apply themselves to the task of investigating the Mycologic Flora of this rich and fertile region. In Central America very small and incomplete collections have as yet been made, and the same may be said of South America and Canada. Of the whole extent of the New World, only the Carolina States of North America can really be said to be satisfactorily known. Asia is still less known, the whole of our vast Indian Empire being represented by the collections made by Dr. Hooker in the Sikkim Himalayas, and a few isolated specimens from other parts. Ceylon has recently been removed from the category of the unknown by the publication of its Mycologic Flora.[B] All that is known of Java is supplied by the researches of Junghuhn; whilst all the rest is completely unknown, including China, Japan, Siam, the Malayan Peninsula, Burmah, and the whole of the countries in the north and west of India. A little is known of the Philippines, and the Indian Archipelago, but this knowledge is too fragmentary to be of much service. In Africa no part has been properly explored, with the exception of Algeria, although something is known of the Cape of Good Hope and Natal. The Australasian Islands are better represented in the Floras published of those regions. Cuba and the West Indies generally are moderately well known from the collections of Mr. C. Wright, which have been recorded in the journal of the Linnæan Society, and in the same journal Mr. Berkeley has described many Australian species.

It will be seen from the above summary how unsatisfactory it must be to give anything like a general view of the geographical distribution of fungi, or to estimate at all approximately the number of species on the globe. Any attempt, therefore, must be made and accepted subject to the limitations we have expressed.

The conditions which determine the distribution of fungi are not precisely those which determine the distribution of the higher plants. In the case of the parasitic species they may be said to follow the distribution of their foster-plants, as in the case of the rust, smut, and mildew of the cultivated cereals, which have followed those grains wherever they have been distributed, and the potato disease, which is said to have been known in the native region of the potato plant before it made its appearance in Europe. We might also allude to _Puccinia malvacearum_, Ca., which was first made known as a South American species; it then travelled to Australia, and at length to Europe, reaching England the next year after it was recorded on the Continent. In the same manner, so far as we have the means of knowing, _Puccinia Apii_, Ca., was known on the Continent of Europe for some time before it was detected on the celery plants in this country. Experience seems to warrant the conclusion that if a parasite affects a certain plant within a definite area, it will extend in time beyond that area to other countries where the foster-plant is found. This view accounts in some part for the discovery of species in this country, year after year, which had not been recorded before; some allowance being made for the fact that an increased number of observers and collectors may cause the search to be more complete, yet it must be conceded that the migration of Continental species must to some extent be going on, or how can it be accounted for that such large and attractive fungi as _Sparassis crispa_, _Helvellas gigas_, and _Morchella crassipes_ had never been recorded till recently, or amongst parasitic species such as the two species of _Puccinia_ above named? In the same manner it is undoubtedly true that species which at one time were common gradually become somewhat rare, and at length nearly extinct. We have observed this to apply to the larger species as well as to the microscopic in definite localities. For instance, _Craterellus cornucopioides_ some ten years ago appeared in one wood, at a certain spot, by hundreds, whereas during the past three or four years we have failed to find a single specimen. As many years since, and in two places, where the goat's-beard was abundant, as it is now, we found nearly half the flowering heads infested with _Ustilago receptaculorum_, but for the past two or three years, although we have sought it industriously, not a single specimen could be found. It is certain that plants found by Dickson, Bolton, and Sowerby, have not been detected since, whilst it is not improbable that species common with us may be very rare fifty years hence. In this manner it would really appear that fungi are much more liable than flowering plants to shift their localities, or increase and diminish in number.

The fleshy fungi, _Agaricini_ and _Boleti_ especially, are largely dependent upon the character of woods and forests. When the undergrowth of a wood is cleared away, as it often is every few years, it is easy to observe a considerable difference in the fungi. Species seem to change places, common ones amongst a dense undergrowth are rare or disappear with the copsewood, and others not observed before take their place. Some species, too, are peculiar to certain woods, such as beech woods and fir woods, and their distribution will consequently depend very much on the presence or absence of such woods. Epiphytal species, such as _Agaricus ulmarius_, _Agaricus mucidus_, and a host of others, depend on circumstances which do not influence the distribution of flowering plants. It may be assumed that such species as flourish in pastures and open places are subject to fewer adverse conditions than those which affect woods and forests.