90 Mycetozoa of North America 



the same shape as the long, cyhndrical phase of C. minutuni. It 

 merges by intermediate steps into the typical form, which may 

 also be said about the other varieties. Furthermore it is not 

 constant, but may be uniformly cylindrical, or compressed and 

 angular. 



5. Craterium aureum (Schum.) Rost. Mon. 124. 1874. 

 Trichia aurea Schum. Enum. PI. Saell. 2: 208. 1803. 



Plasmodium lemon-yellow (Lister). Sporangia gregarious, 

 and globose, obovoid, piriform, or ellipsoid, 0.4 to 0.6 mm. diam., 

 stalked, erect, rugose, and golden yellow, greenish, gray, or white, 

 without a definite lid and dehiscing irregularly; sporangial wall 

 membranous, with deposits of included lime-granules, denser and 

 of a deeper color on top, the wall stouter and more persistent as a 

 cup at the base, which is continued into the cartilaginous stalk. 

 Stalk cylindrical, 0.2 to 0.5 mm. long, stout, furrowed, charged 

 with lime-granules, yellow or reddish, often rising from a circular 

 hypothallus. Capillitium consisting of a network of hyaline 

 threads, with triangular expansions at the axils, connecting angu- 

 lar or irregularly shaped white or yellow lime-knots, often con- 

 fluent in the center as a pseudo-columella. Spores violet-brown, 

 spinulose, 8-10 n diam. 



Type locality: Denmark. 



Habitat: On dead leaves. 



Distribution: Throughout North America, not uncommon. 



Illustration: Lister, Mycetozoa ed. 3. pi. 67. 



Forming small colonies, it may be found almost anywhere on 

 fertile leaf-piles, associated with a dozen or more other leaf-species. 

 It is intermediate between the genera Craterium and Physarum, 

 and retained in Craterium because of the firmer, lower part of the 

 sporangial wall, persisting as a distinct cup. The sporangia are 

 often white, and also the lime in the capillitium. This is not due 

 to fading, and may be observed in freshly formed and unopened 

 sporangia. The same feature is seen in many of the yellow species 

 of Physarum. 



Genus 8. LEOCARPUS Link, Ges. Nat. Fr. Berl. Mag. 3: 

 25. 1809. 



Sporangial wall of two layers, the outer cartilaginous, shining, 

 with deposits of lime on the inner side, the inner layer hyaline. 



