Cribraria 189 



Sporangia purple or violet. 



Sporangia purple, 2 to 2.5 mm. in total height; plas- 



modic granules 2-2.5 n diam.; net irregular. 15. C. purpurea 



Similar to C. purpurea but sporangia smaller and total 



height 0.7 to 1.7 mm.; net regular. 16. C. elegans 



Sporangia violet, minute, less than 1 mm. total height; 



plasmodic granules 0.5-1 ju diam. 17. C. violacea 



1. Cribraria argillacea Pers. Neues Mag. Bot. 1: 91. 1794. 



Plasmodium lead-colored or purplish olive (Lister). Total 

 height 0.75 to 1.5 mm. Sporangia crowded, globose, short- 

 stalked or nearly sessile, 0.5 to 1.2 mm. diam., ochraceous or 

 olivaceous; cup imperfectly defined; sporangial wall often per- 

 sistent throughout, delicately membranous above, stouter to- 

 wards the base, where it is strengthened by few, rather strong 

 ribs, or reticulate all over with strongly or weakly thickened 

 bands forming a net in the upper part with hardly expanded 

 nodes, after the intervening thin membrane has vanished, or 

 merely strands of the thickened portions; plasmodic granules 

 about 1 jji diam. Stalk 0.1 to 0.8 mm. high, furrowed, dark 

 brown, rising from a well-developed hypothallus. Spores ochra- 

 ceous, nearly smooth, 5-6 yu diam. (Plate 12, fig. 3.) 



Type locality: Europe. 



Habitat: On dead wood. 



Distribution: Not uncommon throughout the United States 

 and Canada. 



Illustration: Lister, Mycetozoa ed. 3. pi. 138. 



This species is distinguished from Lindbladia effusa var. sim- 

 plex by the character of the sporangial wall. In C. argillacea, 

 this is delicate in the upper part, forming eventually, by disap- 

 pearance of the intervening membrane, a more or less defined net, 

 often breaking and leaving persistent, thickened strands of the 

 wall. The thickenings and ribs are seen as reticulations in an 

 earlier stage. In some developments, the wall is nearly uniform 

 in texture, and then resembles the wall of L. effusa var. simplex 

 which is without net or strands. There are no disconcerting 

 intermediates to confuse C. argillacea with any other species of 

 the genus Cribraria. 



2. Cribraria macrocarpa Schrad. Nov. Gen. PI. 8. 1797. 



Plasmodium slate-colored (Lister). Total height about 2 mm. 

 Sporangia gregarious or scattered, stalked, globose or turbinate, 



