_, III., p. 104.
1833. _Physarum stromateum_ Link., _Handb._, III., p. 409.
1876. _Chondrioderma stromateum_ (Lk.) Rost., _App._, p. 18.

Sporangia sessile, crowded, spherical, or by mutual pressure irregular,
white; the peridium plainly double, but the layers adhering, the outer
more strongly calcareous, but very frail, almost farinaceous;
hypothallus more or less plainly in evidence, white or pale alutaceous;
columella distinct, though often small, globose, yellowish; capillitium
variable in quantity, sometimes abundant, brown, somewhat branching and
anastomosing outwardly, the tips paler; spores minutely roughened, dark
violaceous, about 10 mu.

This species has the outward seeming of a didymium, but is plainly
different as that genus is here defined, since the calcareous crust,
although inclined to be pulverulent, is made up of minute granules, not
crystals, of lime. The hypothallus is sometimes hardly discoverable,
anon well developed, out-spread, rugulose, far beyond the limits of the
fructification. In his _Monograph_, p. 175, Rostafinski includes here
_Physarum stromateum_ Link. In the Appendix he is inclined to raise
Link's form to the dignity of a distinct species, basing the diagnosis
upon the superposition of the sporangia in certain cases, a feature
entirely unknown to Link's description and of extremely uncertain value,
since by their crowding the sporangia are liable always to be pushed
above each other. We therefore regard _C. stromateum_ (Link) Rost. as a
synonym of the present species, as the description, Link, Handb., III.,
409, indicates, so far as it goes.

3. DIDERMA SIMPLEX (_Schroet._) _Lister._

1885. _Chondrioderma simplex_ Schroet., _Krypt. Fl. Schles._, III.,
1, p. 123.
1911. _Diderma simplex_ List., _Mycetozoa, 2nd ed._, p. 107.

"Plasmodium bright yellowish brown." Sporangia gregarious, sessile,
globose or depressed globose, .3-.5 mm., or anon plasmodiocarpous, brown
or brick-red when fresh, becoming paler, ochraceous, etc.; hypothallus
everywhere in evidence; columella ill-defined; capillitium scanty, the
threads delicate, pale, branching as they join the peridial wall; spores
dull violaceous, slightly roughened, 8-10 mu.

A rather crude, primitive representative of this beautiful genus. The
inner peridium seems to be lacking,--a comfort to Rostafinski! Rare. Our
best specimens are from New Jersey, by courtesy of Dr. C. L. Shear.
These went to fruit on leaves