82 THE MYXOMYCETES 



59. Physarum albescens Ellis 



in Macbride, N. A. Slime-Moulds ed. 2. 86. 1922. 

 PL VI, Figs. 107, 108. 



1893. Physarum auriscalpium Cke. ex Macbride, Bull. Lab. Nat. Hist. Iowa 

 2 : 158, in part. 



1894. Physarum virescens Ditm. var. nitens List., Mycetozoa 59, in part. 

 1899. Leocarpus julvus Macbr., N. A. Slime-Moulds 82. 



1911. Physarum julvum (Macbr.) List., Mycetozoa ed. 2. 60, non Fries. 



Sporangia gregarious or scattered, ovoid or globose, occasionally 

 subplasmodiocarpous, pale yellowish or fulvous, opening irregularly 

 above, stipitate or sessile; peridium double, the outer layer more or 

 less calcareous, the inner delicate, almost indistinguishable, persistent 

 below as a shallow cup; stipe usually long, weak, striate, fulvous or 

 yellow; hypothallus distinct, venulose or more or less continuous; 

 capillitium pallid or white, dense, flattened and expanded at the axes, 

 with here and there below large continuous yellow calcareous nodules; 

 columella none; spore-mass black; spores by transmitted light dark 

 brown, rough, 12-15 ju. The Plasmodium is yellow on fallen leaves and 

 twigs. 



The capillitium is curious, largely flattened and membranous and 

 much like that of Leocarpus, while the general aspect is that of a did- 

 erma. Forms occur, however, in which the capillitium is more typically 

 physaroid; such forms may have but a single layer to the peridium. 

 Reference to the taxonomic history will be found in N. A. Slime- 

 Moulds, ed. 2, pp. 87-89, where the name used by Ellis, P. albescens, 

 was published. 



Iowa, Louisiana, Colorado, Montana, Idaho; Switzerland. 



60. Physarum citrinellum Peck 



Rept. N. Y. Mus. Nat. Hist. 31 : 57. 1879. 

 PL VI, Figs. 109, 110. 



1869. Diderma citrinum Pk., Rept. N. Y. State Mus. 22 : 89, non Fr. 

 1894. Craterium citrinellum (Pk.) List., Mycetozoa 74. 



Sporangia gregarious or scattered, globose, 0.6-0.8 mm. in diameter, 

 short-stipitate, pale yellow or ochraceous, smooth or slightly rough- 

 ened by the presence of minute lime particles; peridium double, the 

 outer calcareous, fragile, the inner very delicate, with here and there 

 a calcareous thickening, ruptured irregularly; stipe very short, half 

 the sporangium, orange-brown, translucent, furrowed, expanded below 

 into an imperfectly defined hypothallus; capillitium abundant, the 

 nodes stellate-angular, large, the internodes delicate, short; spore- 



