Craterium 89 



4. Craterium leucocephalum (Pers.) Ditm. in Sturm, Deutsch. 

 Fl. Pilze 1: 21. 1813. 



Stemonitis leucocephala Pers.; Gmel. Syst. Nat. 2: 1467. 1791. 



Plasmodium rich yellow (Lister). Total height about 1 mm. 

 Sporangia more or less obovoid or turbinate, stalked, erect, white 

 above and brown or reddish brown below, sometimes free of lime 

 in the upper part and then yellowish; lid white, convex, often 

 well developed; sporangial wall thin, yellow, firmer and darker 

 below, usually with lime in the upper part. Stalk cylindrical, 

 plicate, translucent, reddish brown, 0.3 to 0.5 mm. long, rising 

 from a circular hypothallus. Capillitium of large irregular, white 

 lime-knots, rarely yellow, connected by threads with flattened 

 expansions at the axils, often with a prominent pseudo-columella. 

 Spores violet-brown, minutely warted, 7-9 ii diam. 



Var. cylindricum (Massee) Lister, Mycetozoa ed. 2. 97. 1911. 

 Craterium cylindricum Massee, Mon. 268. 1892. 



Sporangia cylindrical, otherwise like the typical form. 



Var. scyphoides (Cooke & Balf.) Lister, Mycetozoa ed. 2. 97. 1911. 

 Physarum scyphoides Cooke & Balf.; Massee, Jour. Myc. 5; 186. 1889. 

 (N. Y. B. G. no. 6193, type material.) 



Sporangia globose or shortly turbinate with a reddish base, 

 dehiscing irregularly. 



Var. rufum G. Lister, Mycetozoa ed. 3. 78. 1925. 



Sporangia somewhat cylindrical with short stalks; reddish 

 brown all over including the well-defined lids. 



Type locality: Europe. 



Habitat: On dead leaves and twigs, sometimes on wood. 



Distribution: The typical form and var. cylindricum are 

 common throughout the United States and Canada; var. scy- 

 phoides, not so common; var. rufum, New York, Pennsylvania, 

 Quebec. 



Illustration: Lister, Mycetozoa ed. 3. pi. 81. 



Lister mentions crystalline discs in the sporangial wall, but 

 these are not always present in American specimens. Numerous 

 variations in the form and coloring of the sporangia are found 

 merging one into another, often in the same large colony. The 

 recognized varieties are therefore centers around which the others 

 are clustered. Var. cylindricum, in its highest development, has 



