T h is genus was first established by T o d e , in his Fungi
Mecklenbergenses selecti, with an excellent character. P e r -
sooN continued the genus, but added to it, two other groupes
of minute plants, possessing no affinity with it, and which have
since been described by D e c a n d o l l e , under the names of
Erysiphe and Ehizoctonia. Sclerotium, as well defined by
T o d e and D e c a n d o l l e , contains, according to the excellent
history of the genus published by the latter author, in the 2d
volume of Mémoires du Museum d ’Histoire Naturelle, 30
species : these are tolerably uniform in structure, though very
variable in appearance ; and notwithstanding the light thrown
upon them in the above-quoted memoir, they may be considered
as a group very little understood.
S ow e rb y ’s Sphceria solida, is truly the plant in question ;
the “ spiculce" observed and figured by him being only extraneous
bodies.
Fig. 1. Plants, natural size. Fig. 2. A single plant. Fig. 3. A section. Fig. 4.
A thin slice All except Fig. 1. more or less magnified.