312 A Monograph of the Myxogastres. 



with particles; spores blackish-brown, threads of capillitium 

 citrin. 



Physarum caespitosum, Schweinitz, Syn., Fung. Amer. Bar., 

 n. 2310; Sacc., Syll., vii., 1, n. 1212. 



On leaves and stems of Rhododendron. Bethlehem ; United 

 States. 



Physarum muscicolum, Pers." 1 



Sporangia turbinate, grey ; stem short, yellowish ; capillitium 

 white ; spores black. 



Physarum muscicolum, Pers., Obs., i., p. 6 ; Pers., Syn., p. 176 ; 

 Alb. and Schw., p. 93; Sacc., Syll., vii., 1, n. 1219. 



On the larger mosses in pine woods, peat mosses, &c. 

 Sweden; Germany. 



Scattered or gregarious, hypothallus not distinct ; stem vari- 

 able in length, about twice as long as sporangium, often reddish; 

 sporangium smooth, at length squamulose, varying from obovate 

 to cylindrical ; threads adnate, white, spores compacted. (Pers.) 



Physarum albicans, Peck. T> <\l^' 



Sporangia whitish, fugacious, except at the base, externally 

 mealy with lime granules, globose, as well as the more per- 

 sistent whitish capillitium ; stem white, tapering upwards, 

 sometimes connate at the base, slightly penetrating ; spores 

 globose, purplish-brown, -00033' in diameter ( = about 8 9 jn). 



Physarum albicans, Peck, 30th Report, State Mus. of N. York, 

 p. 50, pi. ii., figs. 58; Sacc., Syll., vii., 1, n. 1201. 



Didymium sulroscum, Peck. 



Bark and mosses. Adirondack Mts., U. States. 



The fragments of the base of the peridium sometimes remain 

 just below the capillitium, surrounding the stem like a calyx 

 or collar. The stem is even and generally longer than the 

 peridium, which it penetrates. After the spores have fallen 

 the whitish colour of the capillitium becomes apparent. It 

 then resembles a small globose tuft of wool. The plants grew 

 on the branches and mosses of a standing dead birch tree. 



