Sporangia sessile, elongate, creeping but not reticulate, semicircular in transverse section, sometimes globose or depressed globose; peridium double, the outer thick coriaceous, yellow or brown, dehiscing stellately into persistent more or less triangular reflected lobes, remote from the thin, colorless inner wall; columella none; capillitium feebly developed, the nodes white, large, isodiametric; spores bright violet, smooth, 7–8 µ.
This species is not uncommon in the mountains of Colorado where it has been taken at various stations by Bethel. It is reported from Pennsylvania and South Carolina. Raciborski describes it from Java.
In habit it is very much like some forms of P. sinuosum but differs in the depressed, rather than compressed sporangia, and in the brown color of the outer peridium.
7. Physarum alpinum G. List.
- 1910. Physarum alpinum G. Lister, Jour. Bot., XLVII, p. 73.
Sporangia globose and sessile or plasmodiocarpous, dull yellow, smooth or scaly; peridium double, the outer wall densely calcareous, separating irregularly from the membranous inner wall; capillitium densely calcareous, the nodes large, more or less branched, yellow; spores purple brown, closely and minutely warted, 9–14 µ.
This species is based by its author upon a gathering made in California by Dr. Harkness and named by Phillips who received it in England, badhamia inaurata. He seems not to have described it. Since its first appearance, the form has been found repeatedly in the Juras. Specimens are before me from Mt. Rainier believed to be the same. The plasmodiocarpous habit and yellow capillitium separate this from related P. contextum and P. mortoni.
Europe, California, Washington.
8. Physarum diderma Rost.
[Plate XVIII.], Fig. 9.