Æthalium pulvinate one to three inches in diameter, covered with a thick spongy incrustation of lime, white or yellowish toward the base: sporangia convolute, the walls membranous, brittle, charged throughout with round white granules of lime, 1.5-2 µ in diameter: columella none: capillitium of delicate, colorless, anastomosing tubules, bearing toward the center large, white, branching calcareous nodules; spores spherical, or somewhat oval, dark purple-brown, rough-tuberculate, 15-20 µ.
This species differs as pointed out by Professor Sturgis, chiefly in the character of the spores, their unusual size and roughness.[18]
1898. _Erionema_ Penzig, _Die Myx. d. Fl. v. Beutenzorg_, p. 36.
Sporangia plasmodiocarpous but distinct, cylindrical; capillitium intricate, elastic; nodules few.
Sporangia elongate, clustered, pendulous, yellow or grayish yellow, generally stipitate on long flaccid stalks, or sessile and interlacing: stipes yellow, blending with the hypothallus; capillitium intricate, expanding at maturity after the manner of _Arcyria_ to several times the sporangial length, the nodules small, yellow; spores nearly smooth, violaceous-brown, 5-6 µ.
This unique form is near the fuligos which it resembles, especially when sessile, in its intricate sporangia. The spores also are those of the common _Fuligo septica_. The habit is however entirely different. Mr. Fetch describes clusters in Ceylon, hanging free, four to six cm. in length!
1852. _Badhamia_ Berkeley, _Trans. Linn. Soc._, XXI., p. 153. 1875. _Badhamia_ Rostafinski, _Monograph_, p. 139.
Sporangia simple; peridial wall simple, thin, breaking irregularly; capillitium formed of abundant, richly anastomosing tubules, filled throughout their entire length with calcareous granules; the nodes often feebly represented; stipe poorly developed or wanting entirely; columella, except in forms sometimes assigned to the sub-genus _Scyphium_, poorly developed or none; spores frequently adherent in clusters.
The whole genus calls for careful and protracted study; and the present so-called species are like something new on the world; as full of vagaries as though but just entered upon their phylogenetic race.
This genus is closely related to _Physarum_, but differs in having the capillitium calcareous throughout. Forms occur and are included here, in which the capillitium, especially in some parts, is physarum-like, physaroid. Nevertheless, the distinctions hold good as a rule, and are at once diagnostic.