DIDERMA 99 



bit, without in the least disturbing the underlying structure. 

 The inner wall is ashen or gauzy iridescent green, sending back 

 all colors in reflected light. The spores are violet, deeply so 

 when fresh, the capillitium strong and likewise tinted, the colu- 

 mella passing down and blending with the common snow white 

 hypothalline base. The distinct habits of two species are repre- 

 sented in Figs. 5 and 7. In the one the distinct sporangia are 

 associated but not crowded ; in the other all are massed together 

 in quite sethalioid fashion, forming chalky masses of considerable 

 size (2 or 3 cm.), where the sporangia are regular in shape and 

 size by reason of mutual pressure. The plasmodium develops in 

 forests and orchards, among decaying leaves. July-September. 



7. DlDERMA LYALLII MctSSee. 



PLATE XVI., Fig. 2. 

 1892. Diderma lyallii Massee, Man., p. 201. 



Sporangia obovate, more or less closely crowded, white, stipi- 

 tate, about I mm. in diameter, the outer peridium firm, stout, 

 encrusted, especially above, with granular masses of lime, the 

 inner well developed, more or less cartilaginous, opaque, yellow 

 or buff colored ; hypothallus well developed, venulose, white, 

 passing up unchanged to form the short, stout stipe and lower 

 outer peridium ; columella prominent, half the height of the 

 sporangium, brown ; capillitium of short brown threads, rigid, 

 much branched, forming a net, widened irregularly and espe- 

 cially at the net nodes ; spore-mass black, spores by transmitted 

 light bright brown, rough, 15-17 ^. 



A very distinct species ; large, fine showy sporangia in more 

 or less crowded clusters spring from a snow white, common 

 hypothallus. First reported from western Canada. Our speci- 

 mens were collected by Mr. Charles Irish, on the eastern slopes 

 of the Sierras, in Nevada. 



8. DIDERMA TESTACEUM (Sckrad.} Pers. 



1797. Didymium testaceum Schrader, Nov. Gen. Plant., p. 25. 

 i So i. Diderma testaceum Persoon, Syn., p. 167. 



