. 260 Mycetozoa of North America 



Fructification usually plasmodiocarpous. 



Plasmodiocarps short, stout, curved or ring-shaped, 



dark brown. 1. P. chrysosperma 



Plasmodiocarps long, slender, curved or net-like, 



yellow or pale brown. 2. F. vermicularis 



Fructification sporangiate. 



Sporangia sessile, subglobose, dark brown with de- 

 posits of refuse matter; dehiscence either by lobes 

 or circumscissile. 3. P. corticalis 



Sporangia sessile or stalked, small, globose, yellowish; 

 deposits of refuse matter scanty or contracted into 

 large, dark warts. 4. P. minor 



Sporangia sessile, flattened and angular, dark brown 

 with deposits of refuse matter; dehiscence circum- 

 scissile. 5. P. depressa 



Sporangia stalked, minute, dark brown; on leaves. 6. P. pedata 



1. Perichaena chrysosperma (Currey) Lister, Mycetozoa 196. 

 1894. 



Ophiotheca chrysosperma Currey, Quart. Jour. Micr. Sc. 2: 240. 1854. 

 Ophiotheca Wrightii Berk. & Curt.; Berk. Jour. Linn. Soc. 10: 349. 1868. 



Plasmodium pale brown, gray or pink (Lister). Sporangia 

 scattered, sessile, rarely stalked, subglobose or forming curved 

 or ring-shaped plasmodiocarps, 0.2 to 1 mm, diam., chestnut, red- 

 brown, or blackish brown, dehiscing irregularly or the wall break- 

 ing up into areolae; sporangial wall of two layers; outer layer 

 thickened with brown granular matter, which either forms a 

 complete crust or is partially or completely obsolete; inner layer 

 somewhat cartilaginous, pale yellowish, translucent, minutely 

 and faintly papillose. Stalk when present, black, stout, cylindri- 

 cal, 0.1 to 0.7 mm. high. Capillitium abundant, forming a loose 

 network of sparingly branched, yellow threads 2-4 ix diam., ir- 

 regularly constricted, studded with scattered spinules or curved 

 spines 1-6 ^ long. Spores yellowish in mass, paler by transmitted 

 light, minutely warted, 9-10 n diam., rarely 7-8 (x. 



Type locality: England. 



Habitat: On dead wood and bark. 



Distribution: Throughout North America; not uncommon. 



Illustration: Lister, Mycetozoa ed. 3. pi. 184. 



This species forms small colonies, usually on the outer surface 

 of dead bark. In the same development may appear subglobose 

 sporangia and plasmodiocarps, either dehiscing by areolae or ir- 



