134 THE MYXOMYCETES 



In 1876, Harkness and Moore collected in the Sierra Nevada Moun- 

 tains of California forms of Diderma which are described by Phillips 

 (Grev. 5 : 113) as D. geasterodes and D. laciniatum. English author- 

 ities who have examined the material agree that the forms described 

 constitute but a single species, and Lister makes them identical with 

 D. trevelyani (Grev.) Fr. Rostafinski's figs. 161, 162, are evidently 

 reproduced from Fries. Nees von Esenbeck's pi. IX, fig. 4, also repre- 

 sents this species. Massee describes a columella; Lister says there is 

 none. As a matter of fact, the same cluster of sporangia may show 

 some with a columella and some without. In a collection of Morgan's 

 from Ohio, labelled Lepidoderma geaster Link, which seems to belong 

 here, the columellas are uniformly well developed. 



The variety nivale Meylan (Bull. Soc. Vaud. 50 : 189, 1914) is a 

 large, mottled, rugose, often plasmodiocarpous form, occurring in the 

 Swiss Alps. 



Ohio, Colorado, Washington, Oregon, California, Argentina, Chile; 

 Europe. 



18. Diderma asteroides Lister 



Mycetozoa ed. 2. 113. 1911. 

 PI. IX, Figs. 202, 203. 



1902. Chondrioderma asteroides List., Jour. Bot. 40 : 209. 



Sporangia globose or ovoid-globose, the apex more or less acuminate, 

 sessile, sometimes narrowed at the base to a short, thick stalk, brown- 

 or chocolate-tinted, marked at the apex by radiant lines, and at length 

 dehiscent by many reflexing lobes revealing the snow-white adherent 

 middle peridium on the exposed or upper side, the membranous inner 

 peridium often remaining about the spore-mass; columella also white, 

 globose or depressed-globose; capillitium generally colorless, some- 

 what branched, especially above; spores dark violaceous, verruculose, 

 10-12 /x. 



A very beautiful species, recognizable at sight when unopened by 

 the peculiar chocolate brown color; the sporangia smaller than in 

 D. radiatum. When opened, the snow-white flower-like figure, flat 

 against the substratum, is definitive. Very near D. trevelyani but the 

 dehiscence is more regular, and the middle crystalline layer is lacking 

 in the sporangium wall. 



Var. luteum Meylan differs from the typical form in its chamois or 

 yellowish color. 



Colorado, Washington, Oregon, California; Europe. 



