48 THE NORTH AMERICAN SLIME-MOULDS 



distinct, white ; hypothallus none ; capillitium abundant, open, 

 snow white, with rather large angularly stellate nodes ; spore- 

 mass brown, almost black ; spores by transmitted light, pale 

 violet or lilac-tinted, almost smooth, 7.5-10 p. 



Easily distinguished by its white stipe, columella and capil- 

 litium in strong contrast with yellow peridial walls. N. A. F., 

 1395. Massee refers this number erroneously to P. schuma- 

 cheri Rost. The description and specimen do not correspond. 

 By that name the species has, however, been hitherto known 

 in the United States. 



Eastern United States, common ; rare west of the Mississippi. 



26. PHYSARUM LEUCOPUS Link. 



PLATE IX., 7, 7 a, 7 b. 

 1809. Physarum leucopus Link, Dtss., I., p. 27. 



Sporangia gregarious, stipitate, globose, snow-white, with a 

 Didymium-'^k& covering of calcareous particles ; stipe not long, 

 conical or tapering rapidly upward, slightly sulcate, brittle, 

 from an evanescent hypothallus ; columella none or small ; 

 capillitium, consisting of rather long hyaline threads, connect- 

 ing the usual calcareous nodes, which are large, angular, 

 snow white ; spore-mass black ; spores by transmitted light, 

 violet brown, distinctly warted, about 10 /JL. 



The snow white, nearly smooth stem, the small sporangium 

 (^ mm.) covered with loose calcareous granules, distinguish 

 this rare species. It looks like a small Didymium squamulosum. 



Rare. Iowa. Ohio ; Lister. 



27. PHYSARUM RAVENELII (Berk, and Curt.*) Mass. 



1873. Didymium ravenelii Berk, and Curt., Grev., II., p. 53. 



1892. Physarum ravenelii Massee, Mon., p. 281. 



1894. Physarum murinum Lister, Mycctazoa* p. 41. 



1896. Cytidium ravenelii (B. and C.), Morgan, Jour. Cin. Soc., p. 82. 



Sporangia scattered, globose or perfectly spherical, ashy 

 brown, rugulose, stipitate ; stipe elongate, pale brown, erect, 

 generally somewhat fusiform, calcareous, brittle ; hypothallus 



