130 Mycetozoa of North America 



the depressions. This is of value in recognizing the species, al- 

 though not evident in the netted or perforated plasmodiocarps. 



16. Didymium ochroideum G. Lister, Jour. Bot. 69: 297. 1931 

 (N. Y. B. G. no. 986, cotype.) 



Plasmodium? Sporangia scattered, sessile, pulvinate or flat- 

 tened, about 0.5 mm. diam., or forming slender, simple or 

 branched plasmodiocarps, depressed centrally or linearly as in 

 D. anellus, brownish yellow, ochraceous, or tawny; sporangial 

 wall membranous, pale yellow, closely covered with small crystals 

 of lime; floor of sporangium pale yellow, somewhat thickened 

 with scanty lime. Columella indefinite or absent. Capillitium 

 of slender, pale purplish threads, branching and anastomosing. 

 Spores purplish gray or purplish brown, minutely spinulose, 

 7-10 M diam. 



Type locality: Japan. 



Habitat: On dead leaves, herbaceous stems, mosses, etc. 



Distribution: Iowa, Kansas, New York, Ontario, Pennsyl- 

 vania. 



Illustration: G. Lister, Jour. Bot. 69: pi. 598, figs. la-Id. 



This form is very close to D. anellus and differs practically 

 only in the ochraceous color, and the more compact layer of 

 lime-crystals on the sporangial wall. It forms small, solitary 

 developments in contrast to the larger, spreading fruitings of 

 D. anellus. It has little resemblance to D. fulvum except in the 

 tawny or yellowish color. The latter forms larger, more robust, 

 and clustered sporangia and plasmodiocarps, with dense clusters 

 of large lime-crystals, and has entirely different spores. D. och- 

 roideum has now been found fifteen times in the territory men- 

 tioned. In some of the collections, the color is very pale, almost 

 grayish white. 



17. Didymium dubium Rost. Mon. 152. 1874. 



Didymium Wilcsekii Meylan, Bull. Soc. Vaud. Sc. Nat. 44: 290. 1908. 



(N. Y. B. G. nos. 7147, 13107, authentic material); Lister, Mycetozoa 



ed. 2. 134. 1911. 

 Didymium nivicolum Meylan, Bull. Soc. Vaud. Sc. Nat. 57: 40. 1929. (N. Y. 



B. G. no. 7137, authentic material.) 



Plasmodium gray (Lister). Sporangia scattered, sessile, 

 forming pulvinate, elongate, curved, or almost net-like plasmo- 

 diocarps, 1 to 2 mm. wide, 1 mm. to 3 cm. long, 0.3 to 0.5 mm. 



