Chapter M: J. Berkeley (9)

The influence of fungi upon animals in countries other than European is very little known, except in the case of the species of _Torrubia_ found on insects, and the diseases to which silkworms are subject. Instances have been recorded of the occurrence of fungoid mycelium--for in most it is nothing more--in the tissues of animals, in the hard structure of bone and shell, in the intestines, lungs, and other fleshy parts, and in various organs of birds.[V] In some of the latter cases it has been described as a Mucor, in most it is merely cells without sufficient character for determination. It is by no means improbable that fungi may be found in such situations; the only question with regard to them is whether they are not accidental, and not the producers of unhealthy or diseased tissues, even when found in proximity thereto.

There is one phase of the influences of fungi on the lower animals which must not be wholly passed over, and that is the relation which they bear to some of the insect tribes in furnishing them with food. It is especially the case with the _Coleoptera_ that many species seem to be entirely dependent on fungi for existence, since they are found in no other situations. Beetle-hunters tell us that old _Polyporei_, and similar fungi of a corky or woody nature, are always sought after for certain species which they seek in vain elsewhere,[W] and those who possess herbaria know how destructive certain minute members of the animal kingdom are to their choicest specimens, against whose depredations even poison is sometimes unavailing.

Some of the Uredines, as _Trichobasis suaveolens_ and _Coleosporium sonchi_, are generally accompanied by a little orange larva which preys upon the fungus; and in the United States Dr. Bolles informs us that some species of _Æcidium_ are so constantly infested with this red larva that it is scarcely possible to get a good specimen, or to keep it from its sworn enemy. Minute _Anguillidæ_ revel in tufts of mould, and fleshy Agarics, as they pass into decay, become colonies of insect life. Small _Lepidoptera_, belonging to the _Tineina_, appear to have a liking for such _Polyporei_ as _P. sulfureus_ when it becomes dry and hard, or _P. squamosus_ when it has attained a similar condition. _Acari_ and _Psocidæ_ attack dried fungi of all kinds, and speedily reduce them to an unrecognizable powder.

III. What are the influences exerted by fungi on other plants? This is a broad subject, but withal an important one, since these influences act indirectly on man as well as on the lower animals. On man, inasmuch as it interferes with the vegetable portion of his food, either by checking its production or depreciating its quality. On the lower animals, since by this means not only is their natural food deteriorated or diminished, but through it injurious effects are liable to be produced by the introduction of minute fungi into the system. These remarks apply mainly to fungi which are parasitic on living plants. On the other hand, the influence of fungi must not be lost sight of as the scavengers of nature when dealing with dead and decaying vegetable matter. Therefore, as in other instances, we have here also good and bad influences intermingled, so that it cannot be said that they are wholly evil, or unmixed good.

Wherever we encounter decaying vegetable matter we meet with fungi, living upon and at the expense of decay, appropriating the changed elements of previous vegetable life to the support of a new generation, and hastening disintegration and assimilation with the soil. No one can have observed the mycelium of fungi at work on old stumps, twigs, and decayed wood, without being struck with the rapidity and certainty with which disintegration is being carried on. The gardener casts on one side, in a pile as rubbish, twigs and cuttings from his trees, which are useless to him, but which have all derived much from the soil on which they flourished. Shortly fungi make their appearance in species almost innumerable, sending their subtle threads of mycelium deep into the tissues of the woody substance, and the whole mass teems with new life. In this metamorphosis as the fungi flourish so the twigs decay, for the new life is supported at the expense of the old, and together the destroyers and their victims return as useful constituents to the soil from whence they were derived, and form fresh pabulum for a succeeding season of green leaves and sweet flowers. In woods and forests we can even more readily appreciate the good offices of fungi in accelerating the decay of fallen leaves and twigs which surround the base of the parent trees. In such places Nature is left absolutely to her own resources, and what man would accomplish in his carefully attended gardens and shrubberies must here be done without his aid. What we call decay is merely change; change of form, change of relationship, change of composition; and all these changes are effected by various combined agencies--water, air, light, heat, these furnishing new and suitable conditions for the development of a new race of vegetables. These, by their vigorous growth, continue what water and oxygen, stimulated by light and heat, had begun, and as they flourish for a brief season on the fallen glories of the past summer, make preparation for the coming spring.

Unfortunately this destructive power of fungi over vegetable tissues is too often exemplified in a manner which man does not approve. The dry rot is a name which has been given to the ravages of more than one species of fungus which flourishes at the expense of the timber it destroys. One of these forms of dry rot fungus is _Merulius lacrymans_, which is sometimes spoken of as if it were the only one, though perhaps the most destructive in houses. Another is _Polyporus hybridus_, which attacks oak-built vessels;[X] and these are not the only ones which are capable of mischief. It appears that the dry rot fungus acts indirectly on the wood, whose cells are saturated with its juice, and in consequence lose their lignine and cellulose, though their walls suffer no corrosion. The different forms of decay in wood are accompanied by fungi, which either completely destroy the tissue, or alter its nature so much by the abstraction of the cellulose and lignine, that it becomes loose and friable. Thus fungi induce the rapid destruction of decaying wood. These are the conclusions determined by Schacht, in his memoir on the subject.[Y]

We may allude, in passing, to another phase of destructiveness in the mycelium of fungi, which traverse the soil and interfere most injuriously with the growth of shrubs and trees. The reader of journals devoted to horticulture will not fail to notice the constant appeals for advice to stop the work of fungi in the soil, which sometimes threatens vines, at others conifers, and at others rhododendrons. Dead leaves, and other vegetable substances, not thoroughly and completely decayed, are almost sure to introduce this unwelcome element.

Living plants suffer considerably from the predations of parasitic species, and foremost amongst these in importance are those which attack the cereals. The corn mildew and its accompanying rust are cosmopolitan, as far as we know, wherever corn is cultivated, whether in Australia or on the slopes of the Himalayas. The same may also be said of smut, for _Ustilago_ is as common in Asia and America as in Europe. We have seen it on numerous grasses as well as on barley from the Punjab, and a species different from _Ustilago maydis_ on the male florets of maize from the same locality. In addition to this, we learn that in 1870 one form made its appearance on rice. It was described as constituting in some of the infested grains a whitish, gummy, interlaced, ill-defined, thread-like mycelium, growing at the expense of the tissues of the affected organs, and at last becoming converted into a more or less coherent mass of spores, of a dirty green colour, on the exterior of the deformed grains. Beneath the outer coating the aggregated spores are of a bright orange red; the central portion has a vesicular appearance, and is white in colour.[Z] It is difficult to determine from the description what this so-called _Ustilago_ may be, which was said to have affected a considerable portion of the standing rice crop in the vicinity of Diamond Harbour.

Bunt is another pest (_Tilletia caries_) which occupies the whole farinaceous portion of the grains of wheat. Since dressing the seed wheat has been so widely adopted in this country, this pest has been of comparatively little trouble. Sorghum and the small millets, in countries where these are cultivated for food, are liable to attacks from allied parasites. Ergot attacks wheat and rice as well as rye, but not to such an extent as to have any important influence upon the crop. Two or three other species of fungi are sometimes locally troublesome, as _Dilophospora graminis_, and _Septoria nodorum_ on wheat, but not to any considerable extent. In countries where maize is extensively grown it has not only its own species of mildew (_Puccinia_), but also one of the most enormous and destructive species of _Ustilago_.

A singular parasite on grasses was found by Cesati in Italy, in 1850, infesting the glumes of _Andropogon_.[a] It received the name of _Cerebella Andropogonis_, but it never appears to have increased and spread to such an extent as was at first feared.

Even more destructive than any of these is the potato disease[b] (_Peronospora infestans_), which is, unfortunately, too well known to need description. This disease was at one time attributed to various causes, but long since its ascertained source has been acknowledged to be a species of white mould, which also attacks tomatoes, but less vigorously. De Bary has given considerable attention to this disease, and his opinions are clearly detailed in his memoir on _Peronospora_, as well as in his special pamphlet on the potato disease.[c] One sees the cause of the epidemic, he says, in the diseased state of the potato itself, produced either accidentally by unfavourable conditions of soil and atmosphere, or by a depravation that the plant has experienced in its culture. According to these opinions, the vegetation of the parasite would be purely accidental, the disease would be independent of it, the parasite would be able frequently even to spare the diseased organs. Others see in the vegetation of the _Peronospora_ the immediate or indirect cause of the various symptoms of the disease; either that the parasite invades the stalks of the potato, and in destroying them, or, so to speak, in poisoning them, determines a diseased state of the tubercles, or that it introduces itself into all the organs of the plant, and that its vegetation is the immediate cause of all the symptoms of the disease that one meets with in any organ whatever. His observations rigorously proved that the opinions of the latter were those only which were well founded. All the alterations seen on examining spontaneous individuals are found when the _Peronospora_ is sown in a nourishing plant. The most scrupulous examination demonstrates the most perfect identity between the cultivated and spontaneous individuals as much in the organization of the parasite as in the alteration of the plant that nourishes it. In the experiments that he had made he affirms that he never observed an individual or unhealthy predisposition of the nourishing plant. It appeared to him, on the contrary, that the more the plant was healthy, the more the mould prospered.

We cannot follow him through all the details of the growth and development of the disease, or of his experiments on this and allied species, which resulted in the affirmation that the mould immediately determines the disease of the tubercles as well as that of the leaves, and that the vegetation of the _Peronospora_ alone determines the redoubtable epidemic to which the potato is exposed.[d] We believe that this same observer is still engaged in a series of observations, with the view, if possible, of suggesting some remedy or mitigation of the disease.

Dr. Hassall pointed out, many years since, the action of fungous mycelium, when coming in contact with cellular tissue, of inducing decomposition, a fact which has been fully confirmed by Berkeley.

Unfortunately there are other species of the same genus of moulds which are very destructive to garden produce. _Peronospora gangliformis_, B., attacks lettuces, and is but too common and injurious. _Peronospora effusa_, Grev., is found on spinach and allied plants. _Peronospora Schleideniana_, D. By., is in some years very common and destructive to young onions, and field crops of lucerne are very liable to attack from _Peronospora trifoliorum_, D. By.

The vine crops are liable to be seriously affected by a species of mould, which is but the conidia form of a species of _Erysiphe_. This mould, known under the name of _Oidium Tuckeri_, B., attacks the vines in hothouses in this country, but on the Continent the vineyards often suffer severely[e] from its depredations; unfortunately, not the only pest to which the vine is subject, for an insect threatens to be even more destructive.

Hop gardens suffer severely, in some years, from a similar disease; in this instance the mature or ultimate form is perfected. The hop mildew is _Sphærotheca Castagnei_, Lév., which first appears as whitish mouldy blotches on the leaves, soon becoming discoloured, and developing the black receptacles on either surface of the leaf. These may be regarded as the cardinal diseases of fungoid origin to which useful plants are subject in this country.

Amongst those of less importance, but still troublesome enough to secure the anathemas of cultivators, may be mentioned _Puccinia Apii_, Ca., often successful in spoiling beds of celery by attacking the leaves; _Cystopus candidus_, Lév., and _Glæosporium concentricum_, Grev., destructive to cabbages and other cruciferous plants; _Trichobasis Fabæ_, Lév., unsparing when once established on beans; _Erysiphe Martii_, Lév., in some seasons a great nuisance to the crop of peas.

Fruit trees do not wholly escape, for _Roestelia cancellata_, Tul., attacks the leaves of the pear. _Puccinia prunorum_ affects the leaves of almost all the varieties of plum. Blisters caused by _Ascomyces deformans_, B., contort the leaves of peaches, as _Ascomyces bullatus_, B., does those of the pear, and _Ascomyces juglandis_, B., those of the walnut. Happily we do not at present suffer from _Ascomyces pruni_, Fchl., which, on the Continent, attacks young plum-fruits, causing them to shrivel and fall. During the past year pear-blossoms have suffered from what seems to be a form of _Helminthosporium pyrorum_, and the branches are sometimes infected with _Capnodium elongatum_; but orchards in the United States have a worse foe in the "black knot,"[f] which causes gouty swellings in the branches, and is caused by the _Sphæria morbosa_ of Schweinitz.

Cotton plants in India[g] were described by Dr. Shortt as subject to the attacks of a kind of mildew, which from the description appeared to be a species of _Erysiphe_, but on receiving specimens from India for examination, we found it to be one of those diseased conditions of tissue formerly classed with fungi under the name of _Erineum_; and a species of Torula attacks cotton pods after they are ripe. Tea leaves in plantations in Cachar have been said to suffer from some sort of blight, but in all that we have seen insects appear to be the depredators, although on the decaying leaves _Hendersonia theicola_, Cooke, establishes itself.[h] The coffee plantations of Ceylon suffer from the depredations of _Hemiliea vastatrix_, as well as from insects.[i] Other useful plants have also their enemies in parasitic fungi.

Olive-trees in the south of Europe suffer from the attacks of a species of _Antennaria_, as do also orange and lemon trees from a _Capnodium_, which covers the foliage as if with a coating of soot. In fact most useful plants appear to have some enemy to contend with, and it is fortunate, not only for the plant, but its cultivators, if this enemy is less exacting than is the case with the potato, the vine, and the hop.

Forestry in Britain is an insignificant interest compared to what it is in some parts of Europe, in the United States, and in our Indian possessions. In these latter places it becomes a matter of importance to inquire what influence fungi exert on forest trees. It may, however, be predicated that the injury caused by fungi is far outstripped by insects, and that there are not many fungi which become pests in such situations. Coniferous trees may be infested with the species of _Peridermium_, which are undoubtedly injurious, _Peridermium elatinum_, Lk., distorting and disfiguring the silver fir, as _Peridermium Thomsoni_, B.,[j] does those of _Abies Smithiana_ in the Himalayas. This species occurred at an elevation of 8,000 feet. The leaves become reduced in length one-half, curved, and sprinkled, sometimes in double rows, with the large sori of this species, which gives the tree a strange appearance, and at length proves fatal, from the immense diversion of nutriment requisite to support a parasite so large and multitudinous. The dried specimens have a sweet scent resembling violets. In Northern Europe _Cæoma pinitorquum_, D. By., seems to be plentiful and destructive. All species of juniper, both in Europe and the United States, are liable to be attacked and distorted by species of _Podisoma_[k] and _Gymnosporangium_. _Antennaria pinophila_, Fr., is undoubtedly injurious, as also are other species of _Antennaria_, which probably attain their more complete development in _Capnodium_, of which _Capnodium Citri_ is troublesome to orange-trees in the south of Europe, and other species to other trees. How far birch-trees are injured by _Dothidea betulina_, Fr., or _Melampsora betulina_, Lév., or poplars and aspens by _Melampsora populina_, Lév., and _Melampsora tremulæ_, Lév., we cannot say. The species of _Lecythea_ found on willow leaves have decidedly a prejudicial effect on the growth of the affected plant.

Floriculture has to contend with many fungoid enemies, which sometimes commit great ravages amongst the choicest flowers. Roses have to contend against the two forms of _Phragmidium mucronatum_ as well as _Asteroma Rosæ_. Still more disastrous is a species of _Erysiphei_, which at first appears like a dense white mould. This is named _Sphærotheca pannosa_. Nor is this all, for _Peronospora sparsa_, when it attacks roses in conservatories, is merciless in its exactions.[l] Sometimes violets will be distorted and spoiled by _Urocystis Violæ_. The garden anemone is freely attacked by _Æcidium quadrifidum_. Orchids are liable to spot from fungi on the leaves, and recently the whole of the choicest hollyhocks have been threatened with destruction by a merciless foe in _Puccinia malvacearum_. This fungus was first made known to the world as an inhabitant of South America many years ago. It seems next to have come into notoriety in the Australian colonies. Then two or three years ago we hear of it for the first time on the continent of Europe, and last year for the first time in any threatening form in our own islands. During the present year its ravages are spreading, until all admirers of hollyhocks begin to feel alarm lest it should entirely exterminate the hollyhock from cultivation. It is common on wild mallows, and cotton cultivators must be on the alert, for there is a probability that other malvaceous plants may suffer.

A writer in the "Gardener's Chronicle" has proposed a remedy for the hollyhock disease, which he hopes will prove effectual. He says, "This terrible disease has now, for twelve months, threatened the complete annihilation of the glorious family of hollyhock, and to baffle all the antidotes that the ingenuity of man could suggest, so rapidly does it spread and accomplish its deadly work. Of this I have had very sad evidence, as last year at this time I had charge of, if not the largest, one of the largest and finest collections of hollyhocks anywhere in cultivation, which had been under my special care for eleven years, and up to within a month of my resigning that position I had observed nothing uncommon amongst them; but before taking my final leave of them I had to witness the melancholy spectacle of bed after bed being smitten down, and amongst them many splendid seedlings, which had cost me years of patience and anxiety to produce. And again, upon taking a share and the management of this business, another infected collection fell to my lot, so that I have been doing earnest battle with this disease since its first appearance amongst us, and I must confess that, up to a very short time back, I had come in for a great deal the worst of the fight, although I had made use of every agent I could imagine as being likely to aid me, and all that many competent friends could suggest. But lately I was reminded of Condy's patent fluid, diluted with water, and at once procured a bottle of the green quality, and applied it in the proportion of a large tablespoonful to one quart of water, and upon examining the plants dressed, twelve hours afterwards, was delighted to find it had effectually destroyed the disease (which is easily discernible, as when it is living and thriving it is of a light grey colour, but when killed it becomes of a rusty black). Further to test the power at which the plant was capable of bearing the antidote without injury, I used it double the strength. This dose was instant death to the pest, leaving no trace of any injury to the foliage. As to its application, I advocate sponging in all dressings of this description. Syringing is a very ready means, but very wasteful. No doubt sponging consumes more time, but taking into consideration the more effectual manner in which the dressing can be executed alone, it is in the end most economical, especially in regard to this little parasite. I have found it difficult by syringing, as it has great power of resisting and throwing off moisture, and if but a very few are left living, it is astonishing how quickly it redistributes itself. I feel confident, that by the application of this remedy in time another season, I shall keep this collection clean. I believe planting the hollyhock in large crowded beds should be avoided, as I have observed the closer they are growing the more virulently does the disease attack them, whereas isolated rows and plants are but little injured."[m]

The "Gardener's Chronicle" has also sounded a note of warning that a species of Uredine has been very destructive to pelargoniums at the Cape of Good Hope. Hitherto these plants have not suffered much in this country from parasites. Besides these, there are many other less troublesome parasites, such as _Uredo filicum_, on ferns; _Puccinia Lychnidearum_, on leaves of sweet-william; _Uredo Orchidis_, on leaves of orchids, &c.

If we would sum up the influences of fungi in a few words, it could be done somewhat in the following form.

Fungi exert a deleterious influence--

On _Man_,

When eaten inadvertently.
By the destruction of his legitimate food.
In producing or aggravating skin diseases.

On _Animals_,

By deteriorating or diminishing their food supplies.
By establishing themselves as parasites on some species.

On _Plants_,

By hastening the decay of timber.
By establishing themselves as parasites.
By impregnating the soil.

But it is not proved that they produce epidemic diseases in man or animals, or that the dissemination of their multitudinous spores in the atmosphere has any appreciable influence on the health of the human race. Hence their association with cholera, diarrhoea, measles, scarlatina, and the manifold ills that flesh is heir to, as producing or aggravating causes, must, in the present state of our knowledge and experience, be deemed apocryphal.

[A] A detailed account of the peculiar properties of this fungus and
its employment as a narcotic will be found in Cooke's "Seven
Sisters of Sleep," p. 337. It is figured in Greville's
"Scottish Cryptogamic Flora," plate 54.

[B] Pour chaque 500 grammes de champignons coupes en morceaux
d'assez mediocre grandeur, il faut un litre d'eau acidulée par
deux ou trois cuillerées de vinaigre, ou deux cuillerées de sel
gris. Dans le cas ou l'on n'aurait que de l'eau à sa
disposition, il faut la renouveler une ou deux fois. On
laisse les champignons macérer dans le liquids pendant deux
heures entières, puis on les lave à grande eau. Ils sont
alors mis dans de l'eau froide qu'on porte à l'ébullition,
et après un quart d'heure ou une demi-heure, on les retire, on
les lave, on les essuie, et ou les apprête soit comme un
mets spécial, et ils comportent les mêmes assaisonnements
que les autres, soit comme condiment.--_Morel Traité des
Champignons_, p. lix. Paris, 1865.

[C] Smith's "Chart of Poisonous Fungi," fig. 10.

[D] Ibid. fig. 27. It would be well to become acquainted with all
these figures.

[E] "Skin Diseases of Parasitic Origin," by Dr. Tilbury Fox. London,
1863.

[F] Robin, "Hist. Nat. des Végétaux Parasites." Paris, 1853.
Kuchenmeister, "Animal and Vegetable Parasites of the Human
Body." London, Sydenham Society, 1857.

[G] Berkeley, in "Intellectual Observer," Nov., 1862. "Mycetoma," II.
Vandyke Carter, 1874.

[H] Hallier and Zurn, "Zeitschrift fur Parasitenkunde." Jena,
1869-71.

[I] Dr. Lauder Lindsay, "On Microscopical and Clinical Characters of
Cholera Evacuations," reprinted from "Edinburgh Medical
Journal," February and March, 1856; also "Clinical Notes on
Cholera," by W. Lauder Lindsay, M.D., F.L.S., in "Association
Medical Journal" for April 14, 1854.

[J] "Microscopic Examinations of Air," from the "Ninth Annual Report
of the Sanitary Commissioner," Calcutta, 1872.

[K] "Gardener's Chronicle," March 26, 1864.

[L] Gray, G., "Notices of Insects that are Known to Form the Bases of
Fungoid Parasites." London, 1858.

[M] Halsey, "Ann. Lyceum," New York, 1824, p. 125.

[N] Tulasne, "Selecta Fung. Carp." vol. iii. p. 17.

[O] "Berlin Entom. Zeitung," 1858, p. 178.

[P] "Smithsonian Contributions to Knowledge," v. p. 53.

[Q] "Wiegmann Archiv." 1835, ii. p. 354; "Ann. Nat. Hist." 1841,
405.

[R] Leidy, "Proc. Acad. Nat. Sci. Phil." 1851, p. 204.

[S] "Gardener's Chronicle," November 21, 1868.

[T] Corda, "Prachtflora," pl. ix.

[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 Embassy and Legation on the
Effects of the Vine Disease on Commerce, 1859;" "Reports of H.
M. Secretaries of Embassy, &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 circumstances, 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 circumstances 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 débris 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 grass 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_, _Panus_, _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; _Clitocybe_ and _Mycena_ chiefly amongst leaves; _Nolanea_ amongst grass; _Omphalia_ and _Galera_ chiefly in swampy places; _Lepiota_, _Leptonia_, _Psalliota_, _Stropharia_, _Psilocybe_, and _Psathyrella_ mostly in open places and pastures; _Deconica_ and _Panæolus_ mostly on dung; _Entoloma_ and _Clitopilus_ 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 Loveianus_ 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 cucumis_, 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 Neapolitanus_, which was found growing on coffee-grounds at Naples; and more recently Viviani has described another species, _Agaricus Coffeæ_, 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 avellanus_, 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 _Cyphella_ and _Solenia_, like species of _Peziza_, sometimes occur on bark, and of the former genus some on grasses and others on moss.

CLAVARIEI.--The interesting, often brightly-coloured, tufts of _Clavaria_ are usually found amongst grass, growing directly from the ground. Only in rare instances do they occur on dead leaves or herbaceous stems. _Calocera_ probably should be classed 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 epigæa_, 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 _Hypogæi_, 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 grass.

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. _Æthalium_ will grow on spent tan and other substances. Species of _Diderma_ flourish on mosses, jungermanniæ, grass, dead leaves, ferns, &c. _Angioridium sinuosum_, Grev., will run over growing plants of different kinds, and _Spumaria_, in like manner, encrusts living grasses. _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 cucumber 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 _Sphæronemei_, which are variable in their proclivities, although mostly preferring dead herbaceous plants and the twigs of trees. The exceptions are in favour of _Sphæronema_, 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 _Sphæria_. 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 mass. 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 Muscæ_, which is only the conidia of a species of _Achlya_. One species of _Bactridium_ is parasitic on the hymenium of _Peziza_, and _Echinobotryum 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 _Coniferæ_; _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 _Palmaceæ_, and _Endophyllum_ the succulent leaves of houseleek. In _Æcidium_ a few orders seem to be more liable to attack than others, as the _Compositæ_, _Ranunculaceæ_, _Leguminosæ_, _Labiatæ_, &c., whilst others, as the _Graminaceæ_, _Ericaceæ_, _Malvaceæ_, _Cruciferæ_, 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 assumed, because a certain parasite is found developed on a special host, that it is distinct, unless distinctive characters, apart from habitat, can be detected. _Æcidium compositarum_ and _Æcidium 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 _Æcidium_ 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 _Solanaceæ_, does not extend its ravages beyond that natural order, whilst _Peronospora parasitica_ confines itself to cruciferous plants. One species is restricted to the _Umbelliferæ_, another, or perhaps two, to the _Leguminosæ_, another to _Rubiaceæ_, two or three to _Ranunculaceæ_, and two or three to _Caryophyllaceæ_. 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.

The _Physomycetes_ consist of two orders, _Antennariei_ and _Mucorini_, which differ from each other almost as much in habitat as in external appearance. The former, if represented by _Antennaria_, runs over the green and fading leaves of plants, forming a dense black stratum, like a congested layer of soot; or in _Zasmidium_, the common cellar fungus, runs over the walls, bottles, corks, and other substances, like a thick sooty felt. In the _Mucorini_, as in the _Mucedines_, there is usually less restriction to any special substance. _Mucor mucedo_ occurs on bread, paste, preserves, and various substances; other species of _Mucor_ seem to have a preference for dung, and some for decaying fungi, but rotting fruits are nearly sure to support one or other of the species. The two known species of the curious genus _Pilobolus_, as well as _Hydrophora_, are confined to dung. _Sporodinia_, _Syzygites_, &c., nourish on rotten Agarics, where they pass through their somewhat complicated existence.

The _Ascomycetes_ contain an immense number of species, and in general terms we might say that they are found everywhere. The _Tuberacei_ are subterraneous, with a preference for calcareous districts. The _Perisporiacei_ are partly parasitical and partly not. The _Erysiphei_ include those of the former which flourish at the expense of the green parts of roses, hops, maples, poplars, peas, and many other plants, both in Europe and in North America, whilst in warmer latitudes the genus _Meliola_ appears to take their place.

The _Elvellacei_ are fleshy fungi, of which the larger forms are terrestrial; _Morchella_, _Gyromitra_, and _Helvella_ mostly growing in woods, _Mitrula_, _Spathularia_, and _Leotia_ in swampy places, and _Geoglossum_ amongst grass. The very large genus _Peziza_ is divided into groups, of which _Aleuriæ_ are mostly terrestrial. This group includes nearly all the large-sized species, although a few belong to the next. _Lachneæ_ are partly terrestrial and partly epiphytal, the most minute species being found on twigs and leaves of dead plants. In _Phialea_ the species are nearly entirely epiphytal, as is also the case in _Helotium_ and allied genera. Some species of _Peziza_ are developed from the curious masses of compact mycelium called _Sclerotia_. A few are rather eccentric in their habitats. _P. viridaria_, _P. domestica_, and _P. hoemastigma_, grow on damp walls; _P. granulata_ and some others on dung. _Peziza Bullii_ was found growing on a cistern. _P. theleboloides_ appears in profusion on spent hops. _P. episphæria_, _P. clavariarum_, _P. vulgaris_, _Helotium pruinosum_, and others are parasitic on old fungi. One or two species of _Helotium_ grow on submerged sticks, so as to be almost aquatic, a circumstance of rare occurrence in fungi. Other _Discomycetes_ are similar in their habitats to the _Elvellacei_. The group to which the old genus _Ascobolus_ belongs is in a great measure confined to the dung of various animals, although there are two or three lignicolous species; and _Ascophanus saccharinus_ was first found on old leather, _Ascophanus testaceus_ on old sacking, &c. _Ascomyces_ is, perhaps, the lowest form which ascomycetous fungi assume, and the species are parasitic on growing plants, distorting the leaves and fruit, constituting themselves pests to the cultivators of peach, pear, and plum trees.

The _Sphæriacei_ include a very large number of species which grow on rotten wood, bark, sticks, and twigs; another group is developed on dead herbaceous stems; yet another is confined to dead or dying leaves. One genus, _Torrubia_, grows chiefly on insects; _Hypomyces_ is parasitic on dead fungi; _Claviceps_ is developed from ergot, _Poronia_ on dung, _Polystigma_ on living leaves, as well as some species of _Stigmatea_ and _Dothidea_. Of the genus _Sphæria_, a considerable number are found on dung, now included by some authors under _Sordaria_ and _Sporormia_, genera founded, as we think, on insufficient characters. A limited number of species are parasitic on lichens, and one species only is known to be aquatic.

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.