DiDYMIUM 125 



and columellae. D. nigripes forms small, solitary colonies in 

 shaded woods of the uplands, rarely in the marshes, and if so, 

 on higher and dryer ground. It is separated from the two allied 

 species by the dark, almost black stalk, and the small, globose, 

 dark columella. From D. melanospermum it is distinguished 

 by the longer stalk and its translucent character, and the small 

 columella. 



11. Didymium eximium Peck, Rept. N. Y. State Mus. 31: 41. 

 1879. 



Didymium megalosporum (?) Berk. & Curt.; Berk. Grevillea 2: 53. 1873. 

 Didymium nigripes (Link) Fries, var. eximium (Peck) Lister, Mycetozoa 98. 

 1894. 



Plasmodium? Total height 1 to 1.5 mm. Sporangia gre- 

 garious, subglobose, depressed above, umbilicate beneath, 0.4 to 

 0.6 mm. diam., stalked, erect, yellow, tawny, or white; sporangial 

 wall membranous, clothed with yellowish or white stellate crys- 

 tals of lime. Stalk cylindrical, 0.6 to 0.8 mm. high, longitudinally 

 striate, yellowish to reddish brown, translucent. Columella 

 large, more or less discoid, often thin and flat, or rough and 

 spinose, yellow or tawny. Capillitium of delicate, colorless or 

 purplish brown, branching threads. Spores violet-brown, warted 

 or nearly smooth, 7-10 n diam. 



Type locality: New York. 



Habitat: On dead leaves and twigs. 



Distribution: Colorado, *Iowa, Kansas, *Mexico, New 

 Hampshire, New Jersey, New York, North Carolina, Ontario, 

 Pennsylvania, Quebec, Vermont, Virginia. 



Illustration: Lister, Mycetozoa ed. 3. pi. 102, fig. d, as 

 D. nigripes var. eximium. 



This species forms small, solitary colonies in dry places like 

 D. nigripes. It is distinguished from D. nigripes and D. xantho- 

 pus by the frequent sprinkling of yellowish lime over the peridium, 

 which is never present in the other species, and the columella, 

 often consisting of a thin, circular plate, yellowish in color, and 

 to which the capillitium is attached on both sides. The spo- 

 rangia then are flattened considerably, but will be more globose 

 if the columella is thicker. The columella, when thin and disc- 

 like, is usually smooth, but when more convex is often rough or 

 covered with rather long spines. The stalk is usually somewhat 

 paler than that of D. xanthopus, and the spores are somewhat 



