WILCZEKIA 139 



25. Diderma rugosum (Rex) Macbr. 



N. A. Slime-Moulds 105. 1899. 

 PI. IX, Figs. 210, 211. 



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



Sporangia gregarious, scattered, stipitate, white or ashen, rugulose 

 over the whole surface, the ridges marking the lines of subsequent 

 rupture or dehiscence; peridium thin, papyraceous; stipe well de- 

 veloped, equal to or exceeding the sporangium, subulate, almost black; 

 hypothallus none; columella distinct, globose, generally white, some- 

 times small, sometimes penetrating the sporangium to one-half the 

 height; capillitium white or colorless, the filaments freely forked and 

 combined by lateral branches into a loose network attached to the 

 columella and basal wall below and the upper sporangial wall above; 

 spores violaceous brown, warted, 8-10 ix. Plasmodium gray. 



This species is well designated rugosum, and is recognizable at sight 

 by its wrinkled, areolate surface. Related to D. radiatum in the pre- 

 figured dehiscence, but otherwise very distinct. Likely to be over- 

 looked as a prematurely dried physarum. 



Var. sessile Brandza (Bull. Soc. Myc. Fr. 44 : 266, 1929) as described, 

 differs so greatly from the typical form as to suggest specific distinc- 

 tion. The sporangia are small, 0.4-0.8 mm., sessile, the peridium dis- 

 tinctly double, the columella usually rudimentary or lacking, the 

 spores 12-14 ^. 



Var. asiatica Skvortzow 1931, does not seem to differ from the typi- 

 cal form in any significant respect. 



Rare. North Carolina, Florida, Iowa, West Indies; Europe, Asia. 



5. Wilczekia Meylan 

 Bull. Soc. Vaud. Sc. Nat. 56 : 68. 1925. 



Sporangia ovoid, elliptical or subspherical, often somewhat com- 

 pressed transversely; peridium simple, membranous, the entire sur- 

 face covered with amorphous lime granules and plasmodic particles; 

 capillitium of branched and anastomosing colored filaments similar 

 to those of the Didymiaceae; columella present or absent; spores black- 

 ish brown. Described as having the capillitium and columella of 

 Diachea, but differing from that genus and from Leptoderma in the 

 opaque limy peridium wall. 



A single species: 



