108 Mycetozoa of North America 



Habitat: On dead wood, leaves, and mosses. 



Distribution: *California, Colorado, *Ontano, Oregon, 

 *Washington. 



Illustrations: Lister, Mycetozoa ed. 3. pi. 97; 209, as 

 D. antarctica. 



This species, although distinct, resembles D. radiatum and 

 D. Trevelyani in the manner of dehiscence, and may be confused, 

 particularly with the latter. There are often masses of lime 

 within the sporangium between the capillitium and inner wall, 

 and the columella may be minute or almost obsolete. In D. 

 Trevelyani there is a layer of crystalline lime between the two 

 layers of the wall. D. antarticum was described by Sturgis from 

 a collection made by Prof. Thaxter at Punta Arenas, Chile, and 

 the specimens are now in the Herbarium of the New York Botani- 

 cal Garden. It is surely an erratic phase of D. asteroides. The 

 spores do not have raised bands, but show the lines so often seen 

 on old and dried spores due to contraction and pressure. The 

 columellae and capillitia are extremely irregular, accompanied 

 occasionally by spike-like, calcareous processes, and the condi- 

 tions throughout the sporangia are not uniform. Similar ab- 

 normal conditions appear occasionally in developments of other 

 species of Diderma and are mentioned under D. spumarioides 

 and D. simplex. They are due often to changes in temperature 

 or moisture during the formation of the sporangia. Dr. Plunkett 

 (Pub. Univ. Calif. Biol. Sc. 1: 41. 1934), reports as D. antarc- 

 ticum two collections from California, and mentions differences 

 between them and published descriptions and figures of D. 

 antarcticum. Sturgis regarded the specimens collected by Thax- 

 ter in Chile as agreeing with the description of Licea antarctica 

 Speg., and this opinion has been followed by later authors. 



19. Diderma rugosum (Rex) Macbr. N. A. Slime-Moulds 105. 

 1899. 



Chondrioderma rugosum Rex, Proc. Acad. Nat. Sc. Phila. 1893: 369. 1893. 

 (N. Y. B. G. no. 5616, type material.) 



Plasmodium gray (Rex). Sporangia scattered, stalked, rarely 

 sessile, subglobose or hemispherical, 0.4 to 0.5 mm. diam., gray- 

 ish white, brown at the base, wrinkled and depressed between the 

 wrinkles which divide the wall into numerous, irregularly poly- 

 hedral reticulations; sporangial wall single, thin, with scanty 

 deposits of lime in minute granules. Stalk subulate, 0.4 to 0.8 



