104 Mycetozoa of North America 



Rispaud and I found a dozen or so small colonies on the tips of 

 moss in a wet sphagnum swamp in Pike County, Pennsylvania. 

 Another gathering was made in upper Quebec (Mycologia 31 : 342. 

 1939), and has speckled walls apparently without lime. The 

 form has been found repeatedly in Europe in company with 

 Lepidoderma tigrinum, and with indications that the two species 

 may be closely related. 



14. Diderma Trevelyani (Grev.) Fries, Syst. Alyc. 3: 105. 1829. 



Leangium Trevelyani Grev. Scot. Crypt. Fl. pi. 132. 1824. 



Diderma geasterodes Phill. Grevillea 5: 113, 1877. (N. Y. B. G. nos. 5498, 



5677, type material.) 

 Didymium subcastaneum Romell, Fung. Exsicc. no. 100, not published. (N. Y. 



B. G. no. 5577.) 



Plasmodium pale yellow-brown (Lister). Sporangia scattered 

 or clustered, globose or ellipsoid, 0.8 to 1.5 mm. diam., sessile or 

 short-stalked, rarely forming plasmodiocarps, smooth, or angu- 

 lar with areas of dehiscence, orange-brown, reddish brown, or 

 brown; sporangial wall dividing into unequal revolute, petaloid 

 lobes, white and glossy on the inner side ; of three closely connected 

 layers, the outer cartilaginous, brown, the inner delicately mem- 

 branous, giving attachment to the threads of the capillitium, the 

 middle one composed of coarse, irregular crystals of lime. Stalk 

 furrowed, short, reddish brown. Columella minute, globose or 

 subglobose, usually absent. Capillitium profuse, purple or pur- 

 plish brown, somewhat rigid, either forming a network with dark, 

 bead-like thickenings at the nodes and on the threads, or slender 

 and branched with few thickenings. Spores dark violet-brown, 

 with a paler area of dehiscence, spinulose, 10-13 ^t diam. (Plate 

 9, FIG. 3.) 



Type locality: England. 



Habitat: On dead leaves, mosses, etc. 



Distribution: California, Colorado, *Ohio, *Oregon, Virginia, 

 Washington. 



Illustration: Lister, Mycetozoa ed. 3. pi. 91. 



The species is separated from all others of the Leangium section 

 by the layer of crystalline lime between the inner and outer spo- 

 rangial walls. The minute, occasionally stalked columella is often 

 absent throughout, or both conditions may be present in the same 

 colony. It was found repeatedly by Dr. W. C. Sturgis in Colo- 

 rado, and is probably abundant in our western mountains. Mr. 

 Lloyd G. Carr has found it in the mountains of Augusta County, 



