62 Mycetozoa of North America 



no sharp distinctions. P. tropicale is regarded by Lister as a 

 form of the present species. 



38. Physarum megalosporum Macbr. N. A. Slime-Moulds ed. 2. 

 63. 1922. 



Physarum melanospermum Sturg. Mycologia 9: 323. 1917. (N. Y. B. G. no. 

 12805, type.) Not P. melanospermutn Pers. 1794. 



Plasmodium? Sporangia stalked, gregarious, turbinate or 

 discoid, usually umbilicate above, 0.4 to 0.7 mm. diam., grayish 

 white, rugulose; sporangial wall membranous, with abundant 

 deposits of white lime-granules, occasionally brown and charged 

 with refuse matter toward the base. Stalk stout, black or some- 

 times grayish, furrowed, 0.1 to 0.3 mm. long. Capillitium con- 

 sisting of numerous white, angular, branching lime-knots con- 

 nected by short, hyaline threads. Spores dark, brownish purple, 

 minutely and closely spinulose, with a pale, nearly smooth germi- 

 nal spot, 12.5-16 M diam. (Plate 2, figs. 1-3.) 



Type locality: Colorado. 



Habitat: On dead leaves and twigs. 



Distribution: Colorado, Iowa, Kansas. 



Illustration: Lister, Mycetozoa ed. 3. pi. 201, as P. melano- 

 spermum. 



This well-marked species resembles somewhat Badhamia 

 affinis var. orbiculata when stalked, but may be distinguished by 

 the character of the capillitium, the usually larger and darker 

 spores, and the pale areas on the spores. Curiously enough, it is 

 occasionally associated with Didymium Clavus, which it also re- 

 sembles superficially. 



39. Physarum reniforme (Massee) Lister, Mycetozoa ed. 2. 72. 

 1911. 



Tilmadoche reniformis Massee, Mon. 336. 1892. 



Physarum nicaraguense Macbr. Bull. Nat. Hist. S. U. Iowa 2: 382. 1893. 



Badhamia cinerascens Martin, Jour. Wash. Acad. Sc. 22: 88. 1932. 



Plasmodium? Sporangia scattered or clustered, stalked or 

 almost sessile, reniform, obconic, bolster-shaped, or lobed, usually 

 compressed, 0.4 to 0.9 mm. diam., often confluent in clusters of 

 from three to forty or more, grayish white; sporangial wall mem- 

 branous, with clusters of lime-granules. Stalk wrinkled, variable 

 in color, either pale yellow, yellowish brown, or fuscous, usually 



