PHYSARUM 55 



densely calcareous, the nodes large, more or less branched, yellow; 

 spores purple brown, closely and minutely warted, 9-14 /x. 



This species is based by its author upon a gathering made in Cali- 

 fornia by Dr. Harkness and named by Phillips who received it in 

 England, badhamia inavrata. 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 XVIIL, Fig. 9. 



1875. Physarum diderma Rost, Mon., p. 110. 



1898. Physarum didermoides var. Iwidum List, Jour, Bot., XXXVI,, p. 

 162. 



1899. Physarum diderma Rost, Macbr., N. A. S., p. 30. 



1911. Physarum testaceum Sturgis, List, Mycetozoa, 2nd ed., p. 79. 



Sporangia snow-white, clustered, sessile or narrowly adnate, 

 globose or polygonal by mutual compression; peridium double, the 

 outer dense, fragile, thick, calcareous, the inner delicate, remote, 

 translucent, capillitium well developed, the calcareous nodules white, 

 rounded or angular, sometimes uniting to form a pseudo-columella ; 

 spore-mass black; spores purplish, distinctly rough, 10-12 fi. 



A beautiful and distinct species. As others in the group with which 

 it is here associated, it is a physarum with the outward seeming of a 

 diderma. It occurs in Europe, therefore it is safe to assume that 

 Rostafinski saw it. So well marked it is that any good description 

 will define it, and Rostafinski describes it perfectly, adequately.^ 



Mr. Lister having used for another species the name we here apply 

 — see under P. bitecturn — referred this present form to P. dider- 



1 Inasmuch as there has been decided difference of opinion in reference to 

 this particular species, — all judges readers of the same original description, — 

 it has seemed wise to submit an English translation from the celebrated 

 Monograph loc. cit. 



"24. Physarum diderma Rfski. 



"Sporangia sessile, globose, adnate by a narrow base, white. Peridium 

 double; the outer thick, strongly calcareous, very distinctly set off from the 



