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.