PHY S ARUM 81 



Sporangia gregarious, sessile, stipitate, or even plasmodiocarpous ; 

 when stipitate, depressed, varying at times to irregular reniform in the 

 same colony; globose, the peridium strongly calcareous, cinereous- 

 white; stipe variable, generally tapering upward, always distinctly 

 deeply plicate-furrowed throughout, in color dark, opaque, sometimes 

 touched with white or gray; capillitium abundant, the white lime- 

 knots, varying in size and shape, connected by rather long hyaline 

 threads, with here and there an empty node; spore-mass black, by 

 transmitted light, dark, sooty brown, minutely papillose, 10-11.5 ju,. 



This remarkable species, while not at all difficult of recognition 

 to one familiar with its phases, is withal very difficult to define. 

 Normally stipitate, it often shows from the same Plasmodium all sorts 

 of forms, the shape of the fructification dependent apparently upon 

 external conditions prevalent at the time. The amount of calcium 

 also varies, especially in the capillitium, where there is usually much, 

 with a tendency to the formation of something like a pseudo-colu- 

 mella; the outer net in such cases nearly destitute. The calcium in 

 the stipe also varies; the black or brown stipes are, of course, free 

 from it; the gray or white, calcareous. 



In this large and difficult genus, since spore-color is receiving in- 

 creased consideration, — see No. 3 1 preceding, — it is proper to note 

 that in the present case two types appear, one with spore-color under 

 the lens, as described, the other with spores violaceous with no trace of 

 black; unshadowed. 



The preceding description is based on material assembled during 

 forty years. The form is easily discoverable by any collector through- 

 out the entire valley of the Mississippi and eastward to Nova Scotia. 

 For its naming, students in America have vainly waited the decision 

 of those having access to mycologic types in Europe. It seems now 

 certain that the species is extremely rare in the old world if there 

 occurrent ; never seen by any of the earlier taxonomists including Fries 

 and Rostafinski; perhaps adventitious in these later years, although 

 thus far no specimen from Europe has reached this table, ^ P. nef- 

 roideum of Strasburg herbarium turns out, after all, teste Lister, to 

 be P. compressutn Alb. & Schw., which accordingly shall now enjoy 



^ See also, after all our trouble, Jour. Boi., LVIL, p. 106. 



