around the orifice; their ultimate diffusion being due to
moisture washing them over other parts of the same tree, since it is
probable that their natural area of dissemination is not large, the
higher plants, of which they are mostly conditions, being developed on
the same branches. More must be known of the relations between
_Melanconium_ and Tulasne's sphaeriaceous genus _Melanconis_ before
we can appreciate entirely the advantage to _Melanconium_ and some
other genera, that the wide diffusion of their spores should be
checked by involving them in mucus, or their being agglutinated to the
surface of the matrix, only to be softened and diffused by rain. The
spores in many species amongst the _Melanconiei_ are remarkably fine;
those of _Stegonosporium_ have the endochrome partite and cellular.
In _Stilbospora_ and _Coryneum_ the spores are multiseptate, large,
and mostly coloured. In _Asterosporium_ the spores are stellate,
whilst in _Pestalozzia_ they are septate, with a permanent peduncle,
and crested above with two or three hyaline appendages.

[Illustration: FIG. 49.--Spore of _Hendersonia polycystis_.]

[Illustration: FIG. 50.--Spores of _Dilophospora graminis_.]

[Illustration: FIG. 51.--Spores of _Discosia_.]

[Illustration: FIG. 52.--Spore of _Prosthemium betulinum_.]

[Illustration: FIG. 53.--Spore of _Stegonosporium cellulosum_.]

[Illustration: FIG. 54.--Stylospores of _Coryneum disciforme_.]

[Illustration: FIG. 55.--Spores of _Asterosporium Hoffmanni_.]

[Illustration: FIG. 56.--Spores of _Pestalozzia_.]

[Illustration: FIG. 57.--_Bispora monilioides_.]

The _Torulacei_ externally, and to the naked eye, are very similar to
the black moulds, and the mode of dissemination will be alike in both.
The spores are chiefly compound, at first resembling septate threads,
and at length breaking up into joints, each joint of which possesses
the function of a spore. In some instances the threads are connate,
side by side, as in _Torula hysterioides_, and in _Speira_, being
concentrically arranged in laminae in the latter genus. The structure
in _Sporochisma_ is very peculiar, the joints breaking up within an
external tube or membrane. The spores in _Sporidesmium_ appear to
consist of irregular masses of cells, agglomerated into a kind of
compound spore. Most of the species become pulverulent, and the spores
are easily diffused through the air like an impalpable dust. They form
a sort of link between the stylo