Physarum 49 



23. Physarum albescens Ellis; Macbr. N. A. Slime-Moulds ed. 2. 

 86. 1922. (N. Y. B. G. no. 5704, type material.) 



Leocarptis fulvus Macbr. N. A. Slime-Moulds 82. 1899. 



Physarum fulviim (Macbr.) Lister, Mycetozoa ed. 2.60. 1911. Not P.fulvum 

 Fries. 1829. 



Plasmodium yellow (Lister). Sporangia globose or obovoid, 

 0.6 to 0.8 mm. diam., cream-white, pale fulvous, or yellow, nearly 

 smooth or rugulose, stalked or sessile, with a hypothallus of 

 branching, fulvous strands; sporangial wall of two closely con- 

 nected layers, sometimes separable, enclosing abundant deposits 

 of lime-granules. Stalk 0.1 to 0.5 mm. long, fulvous, weak and 

 almost membranous, expanding below into strands of the hypo- 

 thallus. Capillitium a dense persistent network of nearly color- 

 less threads, with membranous expansions at the axils, and 

 usually with scattered, large, angular, often branched, pale yellow 

 or orange lime-knots, but sometimes with scanty lime. Spores 

 purplish brown, spinulose, 10-12 n diam. 



Type locality: Colorado. 



Habitat: On dead leaves, stems, and twigs. 



Distribution: ^California, Colorado, Florida, *Idaho, Iowa, 

 Louisiana, *Montana, *Nevada, *Oregon, Utah, Wisconsin. 



Illustration: Lister, Mycetozoa ed. 3. pi. 66, as P.fulvum. 



This species bears a striking resemblance to the genus Leo- 

 carpus, but can generally be distinguished by the paler color and 

 persistent capillitium. The lime in the capillitium is scattered 

 and occasionally scanty. 



24. Physarum penetrale Rex, Proc. Acad. Nat. Sc. Phila. 1891: 

 389. 1891. (N. Y. B. G. no. 6142, authentic material.) 



Plasmodium orange-yellow (Lister). Sporangia stalked, erect, 

 and globose, ellipsoid, or obovoid, 0.3 to 0.5 mm. diam., gray or 

 pale greenish yellow, smooth; sporangial wall membranous, with 

 innate, scattered clusters of pale yellow or white lime-granules. 

 Stalk erect or curved, 0.5 to 2 mm. high, slender, subulate, solid, 

 translucent, dull red or golden red. Columella an extension of 

 the stalk penetrating the sporangium nearly to the apex, slightly 

 tapering to the expanded end, yellow. Capillitium a close net- 

 work of slender, hyaline threads with triangular expansions at 

 the axils of the branches, springing from the whole length of the 

 columella, persistent after the dispersal of the spores; lime-knots 



