246 A Monograph of the Myxogastres. 



The granulose wall of the sporangium separates the present 

 species from the genus Chondriodcrma. 



Didymium dubium, Rost. (fig. 102). 



Plasmodium pulvinate, arcuate, in crowded clusters, the outer 

 wall white, with stellate crystals of lime, breaking away from 

 inner wall in irregular pieces; threads of capillitium rigid, 

 rarely forking, forming a loose net, furnished with curved spines, 

 spores obscure violet, minutely vcrruculosc, 10 11 /x diameter. 



Didymium dubium, Rost., Mon., p. 153; Sacc., Syll., n. 1298. 



Britain (Lyndhurst) ; Bohemia. 



Sub-Gen. Atriclia. 



Capillitium obsolete ; columella absent. 



The two species constituting the present subgenus are un- 

 doubtedly degenerate species of Didymium, characterized by 

 the^very rudimentary condition, or entire absence of the 

 capillitium. 



Didymium sinapinum, Cooke (figs. 167, 168). K 



Clavate, subcylindrical, or more or less irregular, wall brittle 

 with lime, at first compact, then breaking up into bright yellow, 

 easily detached particles, becoming irregularly ruptured at the 

 apex, basal attenuated stem-like portion darker, often with a 

 purple tinge; hypothallus spreading, thin; mass of spores 

 blackish-purple ; spores globose, dingy lilac, minutely warted, 

 7 9 fi diameter. 



Dulymium sinapinum, Cooke, Brit. Myx., p. 33, fig. 245 ; 

 Sacc., Syll., n. 1319. 



(Type in Herb., Kew.) 



On leaves. Wales (Forden). 



Growing in isolated patches, gregarious or crowded, springing 

 from a common hypothallus, sporangia 1 1 '5 mm. high, usually 

 more or less clavate, now and then irregularly lobed and form- 

 ing a small aethalium consisting of two or three sporangia, 

 bright sulphur-yellow ; in rare instances a few very thin, bifur- 



