100 Mycetozoa of North America 



Habitat: On dead plant stems, twigs, etc., in mountainous 

 regions. 



Distribution: California, *Colorado, *Oregon, ^Washington. 



Illustration: Lister, Mycetozoa ed. 3. pi. 89, figs. a-c. 



This species is not common, and seems to be restricted to the 

 western states. Together with D. Lyallii and D. deplanatum 

 Fries it constitutes a group with related forms. D. deplanatum 

 has not been definitely reported from North America, but may be 

 present. In Europe it is a lowland form resembling D. effusum, 

 but distinguished by the orange colored inner wall. The habit is 

 scattered, not crowded as in D. niveum, and it forms pulvinate 

 or flattened sporangia and plasmodiocarps, which are sometimes 

 annular. The columella is usually almost obsolete, and repre- 

 sented by a thickening of the sporangial floor, or a slight convex 

 elevation. 



9. Diderma Lyallii (Massee) Macbr. N. A. Slime-Moulds 99. 

 1899. 



Chondrioderma Lyallii Massee, Mon. 201. 1892. 



Diderma niveiim (Rost.) Macbr. var. Lyallii Lister, Mycetozoa ed. 2. 105. 

 1911. 



Plasmodium white (Lister). Sporangia crowded, subglobose 

 or obliquely obovoid, 1 to 1.5 mm. diam., sessile or short-stalked, 

 white, cream-white, or mottled with flesh-colored spots, smooth or 

 somewhat wrinkled, usually seated on an abundant white hypo- 

 thallus; sporangial wall of two layers, the outer with dense cal- 

 careous deposits, separating from the membranous inner layer, 

 which has scanty deposits of lime-granules and is pinkish flesh- 

 colored. Stalk short, stout, furrowed, white or ochraceous. 

 Columella hemispherical, globose, clavate, or ligulate, cream- 

 white or flesh-colored. Capillitium consisting of dark purple or 

 colorless, straight or flexuose threads, branching and anastomos- 

 ing. Spores dark brownish purple, rather coarsely warted, 10- 

 15 /i diam. 



Type locality: Fort Colville, Washington. 



Habitat: On dead plant stems, twigs, etc. in mountainous 

 regions. 



Distribution: California, Idaho, Kansas, Nevada, Utah, 

 ^Washington. 



Illustration: Lister, Mycetozoa ed. 3. pi. 90. 



