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 s