[U] Leidy, "Fauna and Flora within Living Animals," in "Smithsonian Contributions to Knowledge."

[V] Murie, in "Monthly Microscopical Journal" (1872), vii. p. 149.

[W] See genus _Mycetophagus_, "Stephen's Manual Brit. Coleopt." p.

132.

[X] Sowerby's "Fungi," plates 289 and 387, fig. 6.

[Y] Schacht, "Fungous Threads in the Cells of Plants," in Pringsheim's "Jahrbuch." Berlin, 1863.

[Z] "Proceedings of the Agri. Hort. Soc. of India" (1871), p. 85.

[a] "Gardener's Chronicle" (1852), p. 643, with fig.

[b] Berkeley, "On the Potato Murrain," in "Jour. Hort. Soc." vol. i.

(1846), p. 9.

[c] De Bary, "Die gegenwartig herrschende Kartoffelkrankheit."

[d] De Bary, "Memoir on Peronospora," in "Annales des Sci. Nat."

[e] "Reports of H. M. Secretaries of Emba.s.sy and Legation on the Effects of the Vine Disease on Commerce, 1859;" "Reports of H.

M. Secretaries of Emba.s.sy, &c., on Manufactures and Commerce, Vine Disease in Bavaria and Switzerland, 1859," pp. 54 and 62.

[f] C. H. Peek, "On the Black Knot," in "Quekett Microscopical Journal," vol. iii. p. 82.

[g] Cooke, "Microscopic Fungi," p. 177.

[h] "Grevillea," i. p. 90.

[i] "Gardener's Chronicle," 1873.

[j] "Gardener's Chronicle," 1852, p. 627, with fig.

[k] "Podisoma Macropus," Hook, "Journ. Bot." vol. iv. plate xii. fig.

6.

[l] Berkeley, in "Gardener's Chronicle," 1862, p. 308.

[m] "Gardener's Chronicle," August 22, 1874, p. 243.

XI.

HABITATS.

It commonly happens that one of the first inquiries which the student seeks to have answered, after an interest is excited in fungi, is--Where, and under what circ.u.mstances, are they to be found? The inexperienced, indeed, require some guide, or much labour will be expended and patience lost in seeking microscopic forms in just such places as they are least likely to inhabit. Nor is it wholly unprofitable or uninteresting for others, who do not claim to be students, to summarize the habitats of these organisms, and learn how much the circ.u.mstances of their immediate surrounding elements influence production. For reasons which will at once be recognized by the mycologist, the most satisfactory method of study will be somewhat that of the natural groups into which fungi are divided.

AGARICINI.--There is such a close affinity between all the genera of this group that it will be a manifest advantage to take together all those fleshy pileate fungi, the fruit of which is borne on folded plates or gills. It must be premised of this group that, for the majority, shade, a moderate amount of moisture, and steady warmth, but not too great heat, are required. A stroll through a wood in autumn will afford good evidence of the predilection of _Agaricini_, as well as some smaller groups, for such spots. A larger proportion will be found in woods, where shade is afforded, than on open heaths or pastures. These wood-loving forms will consist, again, of those which appear on the soil, and those which are found on rotten stumps and decaying trees. Many of those which grow on trees have a lateral stem, or scarcely any stem at all. It may be remarked, that some species which spring from the soil delight most in the shelter of particular trees. The Agarics of a beech wood will materially differ largely from those in an oak wood, and both will differ from those which spring up beneath coniferous trees.

It may be accepted as true of the largest proportion of terrestrial species, that if they do not spring directly from rotten leaves, and vegetable debris in the last stage of decay, the soil will be rich in vegetable humus. A few only occur on sandy spots. The genus _Marasmius_ is much addicted to dead leaves; _Russula_, to open places in woods, springing immediately from the soil. _Lactarius_ prefers trees, and when found in exposed situations, occurs mostly under the shadow of trees.[A] _Cantharellus_, again, is a woodland genus, many of the species loving to grow amongst gra.s.s or moss, and some as parasites on the latter. _Coprinus_ is not a genus much addicted to woods, but is rather peculiar in its attachment to man--if such expression, or one even implying domesticity, might be employed--farmyards, gardens, dunghills, the base of old gateposts and railings, in cellars, on plaster walls, and even on old damp carpets. _Hygrophorus_ loves "the open," whether pastures, lawns, heaths, commons, or up the slopes of mountains, nearly to the top of the highest found in Great Britain. _Cortinarius_ seems to have a preference for woods, whilst _Bolbitius_ affects dung, or a rich soil. _Lentinus_, _Pa.n.u.s_, _Lenzites_, and _Schizophyllum_ all grow on wood. Coming to the subgenera of _Agaricus_, we find _Pleurotus_, _Crepidotus_, _Pluteus_, _Collybia_, _Pholiota_, _Flammula_, _Hypholoma_, and some species of _Psathyra_ growing on wood, old stumps, or charcoal; _Amanita_, _Tricholoma_, and _Hebeloma_ most attached to woods; _c.l.i.tocybe_ and _Mycena_ chiefly amongst leaves; _Nolanea_ amongst gra.s.s; _Omphalia_ and _Galera_ chiefly in swampy places; _Lepiota_, _Leptonia_, _Psalliota_, _Stropharia_, _Psilocybe_, and _Psathyrella_ mostly in open places and pastures; _Deconica_ and _Panaeolus_ mostly on dung; _Entoloma_ and _c.l.i.topilus_ chiefly terrestrial, and the rest variable.

Of special habitats, we may allude to _Nyctalis_, of which the species are parasitic on dead fungi belonging to the genus _Russula_. One or two species of _Agaricus_, such as _Agaricus tuberosus_ and _Agaricus racemosus_, P., grow on decaying Agarics, whilst _Agaricus Loveia.n.u.s_ flourishes on _Agaricus nebularis_ even before it is thoroughly decayed. A few species grow on dead fir cones, others on old ferns, &c. _Agaricus cepoestipes_, Sow., probably of exotic origin, grows on old tan in hothouses. _Agaricus caulicinalis_, Bull, flourishes on old thatch, as well as twigs, &c. _Agaricus juncicola_, Fr., affects dead rushes in boggy places, whilst _Agaricus affricatus_, Fr., and _Agaricus sphagnicola_, B., are attached to bog moss in similar localities. Some few species are almost confined to the stems of herbaceous plants. _Agaricus petasatus_, Fr., _Agaricus cuc.u.mis_, P., and _Paxillus panuoides_, F., have a preference for sawdust. _Agaricus carpophilus_, Fr., and _Agaricus balaninus_, P., have a predilection for beech mast. _Agaricus urticoecola_, B. and Br., seems to confine itself to nettle roots. _Coprinus radians_, Fr., makes its appearance on plaster walls, _Coprinus domesticus_, Fr., on damp carpets. The only epizoic species, according to M. Fries, is _Agaricus cerussatus v. nauseosus_, which has been met with in Russia on the carcase of a wolf; this, however, might have been accidental. Persoon described _Agaricus Neapolita.n.u.s_, which was found growing on coffee-grounds at Naples; and more recently Viviani has described another species, _Agaricus Coffeae_, with rose-coloured spores, found on old fermenting coffee-grounds at Genoa.[B] Tratinnick figures a species named _Agaricus Markii_, which was found in wine casks in Austria. A _Coprinus_ has, both in this country and on the Continent, been found, after a very short time, on the dressing of wounds, where there has been no neglect. A curious case of this kind, which at the time excited great interest, occurred some fifty years since at St.

George's Hospital. Some species appear to confine themselves to particular trees, some to come up by preference on soil in garden pots. Certain species have a solitary, others a gregarious habit, and, of the latter, _Agaricus grammopodius_, Bull, _Agaricus gambosus_, Fr., _Marasmius oreades_, Fr., and some others grow in rings. Hence it will be seen that, within certain limits, there is considerable variation in the habitats of the _Agaricini_.

_Boleti_ do not differ much from _Agaricini_ in their localization.

They seem to prefer woods or borders of woods to pastures, seldom being found in the latter. One species, _B. parasiticus_, Bull, grows on old specimens of _Scleroderma_, otherwise they are for the most part terrestrial.

_Polypori_ also have no wide range of habitat, except in choice of trees on which to grow, for the majority of them are corticolous. The section _Mesopus_, which has a distinct central stem, has some species which prefer the ground. _Polyporus tuberaster_, P., in Italy springs from the _Pietra funghaia_,[C] and is cultivated for food as well as _Polyporus avella.n.u.s_, which is reared from charred blocks of cob-nut trees.

In other genera of the _Polyporei_ similar habitats prevail. _Merulius lacrymans_, Fr., one form of dry rot, occurs in cellars, and too often on worked timber; whilst _Merulius himantoides_, Fr., is much more delicate, sometimes running over plants in conservatories.

HYDNEI.--There is nothing calling for special note on the habitats of these fungi. The stipitate species of _Hydnum_ are some of them found in woods, others on heaths, one on fir-cones, while the rest have similar habitats to the species of _Polyporus_.

AURICULARINI.--The genera _Hymenochoete_, _Stereum_, and _Corticium_, with some species of _Thelephora_, run over corticated or decorticated wood; other species of _Thelephora_ grow on the ground. The Pezizoid forms of _Cyph.e.l.la_ and _Solenia_, like species of _Peziza_, sometimes occur on bark, and of the former genus some on gra.s.ses and others on moss.

CLAVARIEI.--The interesting, often brightly-coloured, tufts of _Clavaria_ are usually found amongst gra.s.s, growing directly from the ground. Only in rare instances do they occur on dead leaves or herbaceous stems. _Calocera_ probably should be cla.s.sed with the _Tremellini_, to which its structure seems more closely allied. The species are developed on wood. The species of _Typhula_ and _Pistillaria_ are small, growing chiefly on dead herbaceous plants.

One or two are developed from a kind of _Sclerotium_, which is in fact a compact perennial mycelium.

TREMELLINI.--These curious gelatinous fungi are, with rare exceptions, developed on branches or naked wood; _Tremella versicolor_, B. and Br., one of the exceptions, being parasitic on a species of _Corticium_, and _Tremella epigaea_, B. and Br., spreading over the naked soil. This completes our rapid survey of the habitats of the _Hymenomycetes_. Very few of them are really destructive to vegetation, for the Agarics and Polypori found on growing trees are seldom to be seen on vigorous, but rather on dead branches or partly-decayed trunks.

The GASTEROMYCETES are far less numerous in species, and also in individuals, but their habitats are probably more variable. The _Hypogaei_, or subterranean species, are found either near the surface or buried in the soil, usually in the neighbourhood of trees.

PHALLOIDEI.--In most cases the species prefer woody places. They are mostly terrestrial, and have the faculty of making their presence known, even when not seen, by the fetid odour which many of them exhale. Some of them occur in sandy spots.

PODAXINEI.--These resemble in their localities the _Trichogastres_.

Species of _Podaxon_ affect the nests of Termites in tropical countries.[D] Others are found growing amongst gra.s.s.

TRICHOGASTRES.--These are chiefly terrestrial. The rare but curious _Batarrea phalloides_, P., has been found on sand-hills, and in hollow trees. _Tulostoma mammosum_, Fr., occurs on old stone walls, growing amongst moss. _Geaster striatus_, D. C., was at one time usually found on the sand of the Denes at Great Yarmouth. Although _Lycoperdon giganteum_, Batsch, occurs most frequently in pastures, or on hedge banks in fields, we have known it to occur annually for some consecutive years in a garden near London. The species of _Scleroderma_ seem to prefer a sandy soil. _Agloeocystis_ is rather an anomalous genus, occurring on the fruit heads of _Cyperus_, in India. _Broomeia_ occurs at the Cape on rotten wood.

MYXOGASTRES.--Rotten wood is one of the most favoured of matrices on which these fungi develop themselves; some of them, however, are terrestrial. _aethalium_ will grow on spent tan and other substances.

Species of _Diderma_ flourish on mosses, jungermanniae, gra.s.s, dead leaves, ferns, &c. _Angioridium sinuosum_, Grev., will run over growing plants of different kinds, and _Spumaria_, in like manner, encrusts living gra.s.ses. _Badhamia_ not only flourishes on dead wood, but one species is found on the fading leaves of coltsfoot which are still green. _Craterium_ runs over almost any substance which lies in its way. _Licea perreptans_ was found in a cuc.u.mber frame heated with spent hops. One or two _Myxogastres_ have been found on lead, or even on iron which had been recently heated. Sowerby found one on cinders, in one of the galleries of St. Paul's Cathedral.

NIDULARIACEI grow on the ground, or on sticks, twigs, chips, and other vegetable substances, such as sawdust, dung, and rotten wood.

The CONIOMYCETES consist of two sections, which are based on their habitats. In one section the species are developed on dead or dying plants, in the other they are parasitic on living plants. The former includes the _Sphaeronemei_, which are variable in their proclivities, although mostly preferring dead herbaceous plants and the twigs of trees. The exceptions are in favour of _Sphaeronema_, some of which are developed upon decaying fungi. In the large genera, _Septoria_, _Ascochyta_, _Phyllosticta_, _Asteroma_, &c., the favourite habitat is fading and dying leaves of plants of all kinds. In the majority of cases these fungi are not autonomous, but are merely the stylosporous conditions of _Sphaeria_. They are mostly minute, and the stylospores are of the simplest kind. The _Melanconiei_ have a preference for the twigs of trees, bursting through the bark, and expelling the spores in a gelatinous ma.s.s. A few of them are foliicolous, but the exceptions are comparatively rare, and are represented chiefly in _Gloeosporium_, species of which are found also on apples, peaches, nectarines, and other fruits. The _Torulacei_ are superficial, having much of the external appearance of the black moulds, and like them are found on decaying vegetable substances, old stems of herbaceous plants, dead twigs, wood, stumps of trees, &c. The exceptions are in favour of such species as _Torula sporendonema_, which is the red mould of cheese, and also occurs on rats' dung, old glue, &c., and _Sporendonema Muscae_, which is only the conidia of a species of _Achlya_. One species of _Bactridium_ is parasitic on the hymenium of _Peziza_, and _Echin.o.botryum atrum_, on the flocci of black moulds.

In the other section of _Coniomycetes_ the species are parasitic upon, and destructive to, living plants, very seldom being found on really dead substances, and even in such rare cases undoubtedly developed during the life of the tissues. Mostly the ultimate stage of these parasites is exhibited in the ruptured cuticle, and the dispersion of the dust-like spores; but in _Tilletia caries_, _Thecaphora hyalina_, and _Puccinia incarcerata_, they remain enclosed within the fruit of the foster-plant. The different genera exhibit in some instances a liking for plants of certain orders on which to develop themselves. _Peridermium_ attacks the _Coniferae_; _Gymnosporangium_ and _Podisoma_ the different species of Juniper; _Melampsora_ chiefly the leaves of deciduous trees; _Roestelia_ attaches itself to pomaceous trees, whilst _Graphiola_ affects the _Palmaceae_, and _Endophyllum_ the succulent leaves of houseleek. In _aecidium_ a few orders seem to be more liable to attack than others, as the _Compositae_, _Ranunculaceae_, _Leguminosae_, _l.a.b.i.atae_, &c., whilst others, as the _Graminaceae_, _Ericaceae_, _Malvaceae_, _Cruciferae_, are exempt. There are, nevertheless, very few natural orders of phanerogamous plants in which some one or more species, belonging to this section of the _Coniomycetes_, may not be found; and the same foster-plant will occasionally nurture several forms.

Recent investigations tend to confirm the distinct specific characters of the species found on different plants, and to prove that the parasite of one host will not vegetate upon another, however closely allied. This admission must not, however, be accepted as universally applicable, and therefore it should not be a.s.sumed, because a certain parasite is found developed on a special host, that it is distinct, unless distinctive characters, apart from habitat, can be detected. _aecidium compositarum_ and _aecidium ranunculacearum_, for instance, are found on various composite and ranunculaceous plants, and as yet no sufficient evidence has been adduced to prove that the different forms are other than varieties of one of the two species. On the other hand, it is not improbable that two species of _aecidium_ are developed on the common berberry, as De Bary has indicated that two species of mildew, _Puccinia graminis_, and _Puccinia straminis_, are found on wheat.

HYPHOMYCETES.--The moulds are much more universal in their habitats, especially the _Mucedines_. The _Isariacei_ have a predilection for animal substances, though not exclusively. Some species occur on dead insects, others on decaying fungi, and the rest on sticks, stems, and rotten wood. The _Stilbacei_ have also similar habitats, except that the species of _Illosporium_ seem to be confined to parasitism on lichens. The black moulds, _Dematiei_, are widely diffused, appearing on herbaceous stems, twigs, bark, and wood in most cases, but also on old linen, paper, millboard, dung, rotting fruit, &c., whilst forms of _Cladosporium_ and _Macrosporium_ are met with on almost every kind of vegetable substance in which the process of decay has commenced.

_Mucedines_, in some instances, have not been known to appear on more than one kind of matrix, but in the far greater number of cases they nourish on different substances. _Aspergillus glaucus_ and _Penicillium crustaceum_ are examples of these universal _Mucedines_.

It would be far more difficult to mention substances on which these moulds are never developed than to indicate where they have been found. With the species of _Peronospora_ it is different, for these are truly parasitic on living plants, and, as far as already known, the species are confined to certain special plants, and cannot be made to vegetate on any other. The species which causes the potato murrain, although liable to attack the tomato, and other species of _Solanaceae_, does not extend its ravages beyond that natural order, whilst _Peronospora parasitica_ confines itself to cruciferous plants.

One species is restricted to the _Umbelliferae_, another, or perhaps two, to the _Leguminosae_, another to _Rubiaceae_, two or three to _Ranunculaceae_, and two or three to _Caryophyllaceae_. All the experiments made by De Bary seem to prove that the species of _Peronospora_ will only flourish on certain favoured plants, to the exclusion of all others. The non-parasitic moulds are scarcely exclusive. In _Oidium_ some species are parasitic, but probably all the parasitic forms are states of _Erysiphe_, the non-parasitic alone being autonomous; of these one occurs on _Porrigo lupinosa_, others on putrefying oranges, pears, apples, plums, &c., and one on honeycomb. _Acrospeira_ grows in the interior of sweet chestnuts, and we have seen a species growing within the hard testa of the seeds of _Guilandina Bondue_, from India, to which there was no external opening visible, and which was broken with considerable difficulty. Several _Mucedines_ are developed on the dung of various animals, and seldom on anything else.