uoides_, 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 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 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; wh