ARCYRIACEJE 245 



outer surface of the bark, which causes the species generally, by 

 protective coloration, to be overlooked. 



Not common. Pennsylvania, Ohio, Missouri. 



C. ARCYRIACE.^ 



Key to the Genera of the Arcyriacese 



A. Peridium becoming fragmentary, but persisting; capillitium non-elastic, 



1. Lachnobolus 



B. Peridium evanescent above, persistent below; capillitium elastic, 



2. Arcyri^ 



C. Capillitium elastic, bearing hamate branches, 3. Heterotrichia 



1. Lachnobolus Fries. 

 1829. Lachnobolus Fries, Syst. Myc, III., p. 177. 



Sporangia distinct, sessile or nearly so, globose or cylindric, often 

 distorted, scattered or densely crowded, the peridium extremely thin, 

 ruptured irregularly, and persistent in fragments; capillitium attach- 

 ed at numerous points to the sporangial wall, forming a dense net, 

 the threads warted or spinulose, non-elastic. 



Species of this genus are easily distinguished from those of the 

 next by the peculiar fragile peridium and the inelastic capillitium. 



Key to the Species of Lachnobolus 



A. Sporangia pale yellow, on fallen flowers and fruit-burs of Castanea, 



1. L. globosus 



B. Sporangia rosy or copper-colored, at length ochraceous, 



2. L. occidentalis 



1. Lachnobolus globosus (Schiv.) Rost. 



1822. Arcyria glohosa Schw., Syn. Fung. Carol., No. 400. 

 1875. Lachnobolus globosus (Schw.) Rost., Mon., p. 283. 

 1894. Arcyria albida Pers. (in part) Lister, Mycetozoa, p. 186. 



Sporangia on the spines of fallen chestnut burs, scattered, pale yel- 

 low or whitish, small, globose, the peridium early evanescent above, 

 more persistent below, stipitate; stipe small, tapering upward, from 

 a small hypothallus; capillitium a dense but not expanding network 

 attached chiefly to the lower portion of the sporangial wall, minutely 



