e stylosporous
conditions of _Sphaeria_. 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
Muscae_, 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.

In the other section of _Coniomycetes_ the species are parasitic upon,
and destructive to, living plants, very seldom being found on
really dead substances, and even in such rare cases undoubtedly
developed during the life of the tissues. Mostly the ultimate stage
of these parasites is exhibited in the ruptured cuticle, and the
dispersion of the dust-like spores; but in _Tilletia caries_,
_Thecaphora hyalina_, and _Puccinia incarcerata_, they remain enclosed
within the fruit of the foster-plant. The different genera exhibit
in some instances a liking for plants of certain orders on which
to develop themselves. _Peridermium_ attacks the _Coniferae_;
_Gymnosporangium_ and _Podisoma_ the different species of Juniper;
_Melampsora_ chiefly the leaves of deciduous trees; _Roestelia_
attaches itself to pomaceous trees, whilst _Graphiola_ affects the
_Palmaceae_, and _Endophyllum_ the succulent leaves of houseleek. In
_AEcidium_ a few orders seem to be more liable to attack than
others, as the _Compositae_, _Ranunculaceae_, _Leguminosae_, _Labiatae_,
&c., whilst others, as the _Graminaceae_, _Ericaceae_, _Malvaceae_,
_Cruciferae_, are exempt. There are, nevertheless, very few natural
orders of phanerogamous plants in which some one or more species,
belonging to this section of the _Coniomycetes_, may not be found; and
the same foster-plant will occasionally nurture several forms.
Recent investigations tend to confirm