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.