late crystals of lime,
breaking up gradually and falling away. Stipe erect or sometimes bent at
the apex, variable in length, rarely wanting, from pale brown to
blackish in color, rising from a small hypothallus; the columella
reaching the center, brown or blackish, rough, convex, subglobose or
pulvinate, substipitate. Capillitium of slender colorless threads,
radiating from the columella and more or less branched outwardly. Spores
globose, very minutely warted, violaceous, 8-10 mic. in diameter. Plate
XII, Fig. 39.

Growing in vast abundance in Spring on old leaves, bark, wood, etc.
Sporangium .4-.6 mm. in diameter, the stipe scarcely longer but usually
shorter than the diameter of the sporangium rarely absent. It is
considered by Lister to be a variety of _D. farinaceum_; it differs from
this species in its smaller and less-depressed sporangium and in its
smaller nearly smooth spores.

_B. Sporangia sessile._

6. DIDYMIUM EFFUSUM, Link. Sporangia gregarious or scattered, sessile on
a flattened base, convex above, various in shape, subrotund or by
confluence effused and venosely creeping; the wall very thin and
pellucid, invested with a thin flocculose layer of minute crystals of
lime. The columella hemispheric, rugulose, usually snow-white.
Capillitium of very slender colorless threads, furnished with numerous
minute protuberances, much branched and combined into a dense net.
Spores globose, very minutely warted, dark violaceous, 10-11 mic. in
diameter.

Growing on old leaves, wood, etc. Sporangium about .5 mm. in diameter or
thickness, sometimes confluent and more or less elongated as a
plasmodiocarp. This species is reported from the United States, but I
have seen no specimens.

7. DIDYMIUM PHYSAROIDES, Pers. Sporangia roundish or hemispheric, more
or less irregular and deformed, sessile or with a very short stipe, and
closely crowded together upon a strongly-developed common hypothallus;
the wall a dark colored membrane, with a thin layer of stellate crystals
of lime. The columella large and thick, divided into cells which are
filled with irregular lumps of lime, common to all the sporangia.
Capillitium of stout threads, usually simple, only rarely branched,
furnished with numerous fusiform swellings. Spores globose, minutely
warted, dark violaceous, 12-14 mic. in diameter.

Growing on old wood, bark, moss, etc. Reported from Carolina by Curtis.
It is said superficially to resemble somewhat _Physarum diderm