DiANEMA 269 



The descriptions indicate little on which to base three species in 

 two genera, and the slight differences appear to be of the kind of 

 variation seen in so many of the more common forms. Until 

 more is known about these forms, it seems better to follow the 

 lead of Miss Lister in regarding them all as probably one species. 



3. Dianema depressum Lister, Mycetozoa 204. 1894. (N. Y. 

 B. G. no. 11302, authentic material.) 



Cornuvia depressa Lister, Jour. Bot. 29: 264. 1891. 



Plasmodium white or rosy red (Lister). Sporangia solitary 

 or clustered, forming sessile, flattened, pulvinate plasmodiocarps, 

 2 to 10 mm. wide, about 0.3 mm. thick, shining violet when im- 

 mature, glossy and grayish brown when mature; sporangial wall 

 membranous, smooth or minutely reticulate, translucent, yel- 

 lowish or lilac-gray, marked on the inner side with the persistent 

 ends of the capillitium when the rest of the threads have fallen 

 away. Capillitium profuse, consisting of pale yellowish gray, 

 straight, rigid, slender threads 0.5-2 jx thick, minutely papillose 

 on one side, united into numerous small, pencil-like clusters, 

 anastomosing above and below, the ends of the pencils attached 

 to the sporangial wall by abruptly acuminate tips, at length 

 breaking away in an elastic web. Spores in mass lilac-gray or 

 drab, pale yellowish gray by transmitted light, closely reticulate 

 over the greater part of the surface with raised bands forming a 

 border 0.5-1 n broad, the remaining part marked with broken or 

 very loose reticulation, 6-9 ii diam. 



Type locality: England. 



Habitat: On dead wood and sticks. 



Distribution: Colorado, *Oregon, *Washington. 



Illustration: Lister, Mycetozoa ed. 3. pi. 190. 



Another very rare species, with only three records from North 

 America. 



4. Dianema corticatum Lister, Mycetozoa 205. 1894. (N. Y. 



B. G. no. 11299, authentic material, Sande, Norway.) 



Plasmodium pink (Lister). Sporangia either hemispherical, 

 about 1 mm. diam., or, more often forming elongate, annular, 

 or netted plasmodiocarps 3 to 30 mm. long, shining or opaque, 

 chestnut or purplish brown; sporangial wall ochraceous olive, 

 composed of two layers, the outer cartilaginous, densely granular, 



