IQ4 THE NORTH AMERICAN SLIME-MOULDS 



6. ARCYRIA INCARNATA NODULOSA Macbride n. var. 



PLATE III., Fig 8. 



Sporangia small, about i mm. high when unexpanded, 

 crowded in clusters of varying size, dull red or brownish, stipi- 

 tate ; the peridium evanescent except the cup ; stipe very short, 

 concolorous, plicate as the cup, or both smooth and unmarked ; 

 capillitium centrally attached, slowly expanded, open-meshed, 

 dense, the threads even, 5-6 p wide, expanded frequently in 

 globose, spinulose, or papillate-reticulate nodules, especially at 

 points of intersection, marked everywhere by close-set, trans- 

 verse, sharp-edged ridges, which encircle the thread and show 

 no trace of spiral arrangement ; spore-mass brown or red brown ; 

 spores by transmitted light pale yellow or colorless, minutely 

 but distinctly roughened, globose, 10-12 /u,. 



This variety is not distantly related to the preceding, as 

 shown by the centrally attached capillitial mass, but differs in 

 several definite particulars ; the sporangia are much smaller, 

 of an entirely different color, with longer stipes, larger, rougher 

 spores ; the capillitium is also peculiar, the threads unusually 

 wide and densely corrugated transversely, expanding at frequent 

 intervals into globose nodules which are sometimes double the 

 width of the thread. In color this suggests A. affinis Rost, but 

 corresponds in no other particular. 



Apparently not common. For our material, we are indebted 

 to Mr. Hugo Bilgram of Pennsylvania. 



7. ARCYRIA FERRUGINEA Sauter. 



1841. Arcyria ferruginea Saut., Flora, XXIV., p. 316. 



1881. Arcyria macrospora Peck, Rep. N. Y. Mus., XXXIV., p. 43. 



1888. Arcyria aurantiaca Raunkiaer, Myx. Dan., p. (44). 



Sporangia ovoid or short cylindric, crowded or gregarious, 

 dull red or brownish, stipitate ; stipe about equal to the sporan- 

 gium, dark brown or black ; hypothallus well developed, mem- 

 branous, yellowish brown, continuous ; calyculus large, wide and 

 shallow, smooth ; capillitium centrally attached, when fresh, 

 brick red in color, fading on exposure, the threads of uneven 



