Physarum rubiginosum

Physarum rubiginosum Fries, Symb. Gast. 21. 1817
Leangium rubiginosum Fries, Stirp. Femsj. 83. 1825. (Nomen nudum.) Physarum fulvum Fries, Syst. Myc. 3: 143. 1829.
Sporangiate, sessile, globose or cylindric, sometimes narrowed to a stalk-like base, 0.5-0.8 mm. in diameter, rarely plasmodiocarpous, gregarious or clustered, olive-brown, reddish-brown, or scarlet, sometimes white-incrusted ; peridium thin, usually rugulose, the lime deposits continuous or in the form of calcareous scales ; capillitium dense, the nodes large, angular, branched, dull orange to rusty-brown, sometimes red inside and paler outside; spores grayish-black in mass, grayishviolet by transmitted light, minutely spinulose, 9-12 /x in diameter; Plasmodium orange-red or scarlet.
Type locality: Sweden.
Habitat: Dead wood and moss.
Distribution: Maine to Washington (state), south to Florida and Colorado; Europe.