34 Mycetozoa of North America 



there is no refuse matter in the stalks as in varieties of Physarum 

 nutans which it also resembles at times. 



2. Physarum melleum (Berk. & Br.) Massee, Mon. 278. 1892. 



Didymium melleum Berk. & Br. Jour. Linn. Soc. 14: 83. 1873. 



Physarum perfectum M. E. Peck; Peck & Gilb. Am. Jour. Bot. 19: 134. 1932. 



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

 bose, about 0.5 mm. diam., yellow or brownish yellow; sporangial 

 wall membranous, rugulose, persistent at the base, yellowish, with 

 small, yellow lime-granules. Stalk white, buff, yellow, or orange, 

 stout, opaque, chalky in section, charged with lime-granules. 

 Columella short, conical. Capillitium of irregularly branching, 

 delicate, hyaline threads, often expanded at the axils, with white 

 or yellow lime-knots, usually large and angled, but various in size 

 and shape. Spores violet-brown, almost smooth, 7-10 m diam. 



Type locality: Ceylon. 



Habitat: On dead leaves; common and abundant. 



Distribution: Throughout the eastern United States; On- 

 tario, *Oregon, Quebec, and the tropics. 



Illustration: Lister, Mycetozoa ed. 3. pi. 23. 



A variety with orange stalks has been found on two occasions 

 in Ontario. Physarum perfectum M. E. Peck, from Oregon, is 

 perhaps a pale, robust form of P. melleum. 



3. Physarum sulphureum Alb. & Schw. Consp. Lung. 93. 1805. 



Physarum variabile Rex, Proc. Acad. Nat. Sc. Phila. 1893: 371. 1893. (N. Y. 

 B. G. no. 6149, type material.) 



Plasmodium? Sporangia gregarious, stalked, sessile or form- 

 ing plasmodiocarps, piriform, subglobose, or obovoid, rugulose, 

 0.5 to 0.8 mm. diam., sulphur or olive-yellow; sporangial wall 

 membranous, with dense clusters of yellow lime-granules. Stalk 

 stout, white, dirty white, yellowish, or brownish, short, charged 

 with lime. Columella none. Capillitium with many, large, ir- 

 regular, often branched and confluent, white or yellow lime-knots. 

 Spores violet-brown, spinulose, 9-11 n diam. (Plate 7, fig. 2.) 



Var. sessile Hagelstein, Mycologia 31: 346. 1939. 

 Physarum variabile Rex var. sessile Lister, Jour. Bot. 36: 114. 1898. 

 Physarum sessile Brandza; Lister, Mycetozoa ed. 3. 55, in part, pi. 22, fig. b 

 {non a). 1925. 



