Fungi: Their Nature and Uses

by M. C. Cooke

We have thus rapidly, briefly, and casually indicated the habitats to which the majority of the larger groups of fungi are attached, regarding them from a systematic point of view. There is, however, another aspect from which we might approach the subject, taking the host or matrix, or in fact the habitat, as the basis, and endeavouring to ascertain what species of fungi are to be found in such positions. This has partly been done by M. Westendorp;[E] but every year adds considerably to the number of species, and what might have been moderately accurate twelve years since can scarcely be so now. To carry this out fully a special work would be necessary, so that we shall be content to indicate or suggest, by means of a few illustrations, the forms of fungi, often widely distinct in structure and character, to be found in the same locality.

The stems of herbaceous plants are favourite habitats for minute fungi. The old stems of the common nettle, for example, perform the office of host to about thirty species.[F] Of these about nine are Pezizæ, and there are as many sphæriaceous fungi, whilst three species of Dendryphium, besides other moulds, select this plant. Some of these have not hitherto been detected growing on any other stems, such as Sphæria urticæ and Lophiostoma sex-nucleatum, to which we might add Peziza fusarioides and Dendryphium griseum. These do not, however, include the whole of the fungi found on the nettle, since others are parasitic upon its living green parts. Of these may be named Æcidium urticæ and Peronospora urticæ, as well as two species described by Desmazières as Fusisporium urticæ and Septoria urticæ. Hence it will be seen how large a number of fungi may attach themselves to one herbaceous plant, sometimes whilst living, but most extensively when dead. This is by no means a solitary instance, but a type of what takes place in many others. If, on the other hand, we select such a tree as the common lime, we shall find that the leaves, twigs, branches, and wood bear, according to M. Westendorp,[G] no less than seventy-four species of fungi, and of these eleven occur on the leaves. The spruce fir, according to the same authority, nourishes one hundred and fourteen species, and the oak not less than two hundred.

It is curious to note how fungi are parasitic upon each other in some instances, as in that of Hypomyces, characteristic of the genus, in which sphæriaceous fungi make hosts of dead Lactarii, &c. We have already alluded to Nyctalis, growing on decayed Russulæ, to Boletus parasiticus, flourishing on old Scleroderma, and to Agaricus Loveianus, on the pileus of Agaricus nebularis. To these we may add Torrubia ophioglossoides and T. capitata, which flourish on decaying Elaphomyces, Stilbum tomentosum on old Trichia, Peziza Clavariarum on dead Clavaria, and many others, the mere enumeration of which would scarcely prove interesting. A very curious little parasite was found by Messrs. Berkeley and Broome, and named by them Hypocrea inclusa, which makes itself a home in the interior of truffles. Mucors and moulds flourish on dead and decaying Agarics, and other fleshy forms, in great luxuriance and profusion. Mucor ramosus is common on Boletus luridus, and Syzygites megalocarpus on Agarics, as well as Acrostalagmus cinnabarinus. A very curious little parasite, Echinobotryum atrum, occurs like minute nodules on the flocci of black moulds. Bactridium Helvellæ usurps the fructifying disc of species of Peziza. A small Sphinctrina is found both in Britain and the United States on old Polypori. In Sphæria nigerrima, Nectria episphæria, and two or three others, we have examples of one sphæriaceous fungus growing upon another.

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 cœpestipes, 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 cœspitosa, 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?