220 THE NORTH AMERICAN SLIME-MOULDS 



3. Cribraria iniinutissima Schiveinitz. 



Plate XVIL, Figs. 6, 6 a. 

 1832, Cribraria minutissima Schw., N. A. F., No. 2362. 



Sporangia scattered, orange or nut-brown, very minute, .1-.3 mm. 

 or less, globose or ellipsoidal, stipitate, erect or nodding; hypothallus 

 none; stipe short, 1-3 times the sporangium, filiform, tapering up- 

 ward, brown ; the calyculus variable, sometimes well marked and 

 separated from the net when fully mature, by a shallow constriction, 

 more commonly small or entirely wanting, especially in the spher- 

 ical sporangia; net simple, large meshed, without nodal expansions, 

 the threads flattened; spore-mass yellow, spores by transmitted light, 

 pale, nearly smooth, 5-6 ju. 



A most beautiful tiny species. Generally in all the specimens before 

 us, a perfect, spherical net, firm enough to retain its place and struc- 

 ture after all the spores have been scattered. When mature the 

 spore-mass seems to roll about as a ball, freely within the net, the 

 spores being thus gradually dispersed. The calyculus when present is 

 without veins. C. minima Berk. & C, and C. microscopica Berk. & 

 C. are doubtless the same thing. Grev., II., p. 67, 1823. See also 

 BoL Gaz., XIX., 397. 



Rare. Pennsylvania, South Carolina, Missouri, Iowa; Black Hills, 

 South Dakota. 



4. Cribraria rufa (Roth) Rost. 



Plate XIX., Fig. 8. 



1788. Stemonitis rufa Roth, Fl. Germ., I., p. 548. 



1794. Cribraria rufescens Pers., Roemer, N. Mag. Bot., I., p. 91. 



1797. Cribraria fulva Schrad., Nov. Gen. PL, p. 5. 



Sporangia scattered, subglobose or turbinate, dark or reddish orange, 

 .5-.7 mm. in diameter, erect, stipitate ; stipe about equalling the 

 height of the sporangium or longer, dark brown or black; calyculus 

 one-third to one-half the sporangium, the margin toothed, the wall 

 ribbed and continuous with the open wide-meshed net; the network 

 deep yellow or orange, the threads flattened ; the nodes not thickened, 

 little differentiated ; spores concolorous, by transmitted light, pale 

 yellow, verruculose, 5-7 ju,. 



