CRIB R ARIA 159 



height, rough from deposit of plasmodic refuse ; spores, in mass 

 yellowish, globose, smooth, S-i i fi. 



This curious little species, well described by its discoverer, 

 appears to be very rare. At least it is seldom collected ; over- 

 looked by reason of its minuteness. It affects the bark of 

 species of Quercus, and seems to be associated there with Clasto- 

 derma debaryanum. N. A. F., 2497. 



Pennsylvania, Maine. 



E. CRIBRARIE^:. 



Sporangia distinct, more or less closely gregarious, stipitate, 

 the peridium opening, especially above, by a well-defined network 

 formed from thickenings in the original sporangial wall. 



Key to the Genera of the Cribrarieae. 



A. Peridial thickenings in form of an apical net with definite thickenings 



at the intersections of the component threads . . i. CRIBRARIA 



B. Peridial thickenings in form of parallel meridional ribs connected by 



delicate transverse threads ... 2. DICTYDIUM 



i. Cribraria (Pers.} ScJirader. 



1794. Cribraria Persoon, Rb'mer, N. Bot. Mag., I., p. 91 (in part). 

 1797. Cribraria Schrader, Nov. Gen. Plant., p. i. 



Sporangia distinct, gregarious or closely crowded, globose or 

 obovoid, stipitate ; the stipe of very varying length ; the peri- 

 dium simple, marked within by distinct and peculiar, granular, 

 thickenings, which below take the form of radiating ribs, sup- 

 porting the persisting cup, calyculus, and above, by extremely 

 delicate anastomosing branches, unite to weave a more or less 

 regular net with open polygonal meshes ; spores various, more 

 often yellowish or ochraceous, sometimes brown, reddish, or 

 purple. 



The genus Cribraria, as limited by Persoon, included all forms 

 in which the peridium is thin, evanescent half-way down, or 



