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. Mr. Phillips has recently indicated the species of fungi found by him on charcoal beds in Shropshire,[H] but, useful as it is, that only refers to one locality. A complete list of all the fungi which have been found growing on charcoal beds, burnt soil, or charred wood, would be rather extensive. The fungi found in hothouses and stoves are also numerous, and often of considerable interest from the fact that they have many of them never been found elsewhere. Those found in Britain,[I] for instance, are excluded from the British Flora as doubtful, because, growing upon or with exotic plants, they are deemed to be of exotic origin, yet in very few cases are they known to be inhabitants of any foreign country. Some species found in such localities are not confined to them, as _Agaricus coepestipes_, _Agaricus cristatus_, _Æthalium vaporarium_, &c. It is somewhat singular that certain species have a predilection for growing in proximity with other plants with which they do not appear to have any more intimate relation. Truffles, for instance, in association with oaks, _Peziza lanuginosa_ under cedar-trees, _Hydnangium carneum_ about the roots of _Eucalypti_, and numerous species of _Agaricini_, which are only found under trees of a particular kind. As might be anticipated, there is no more fertile habitat for fungi than the dung of animals, and yet the kinds found in such locations belong to but a few groups. Amongst the _Discomycetes_, a limited number of the genus