144 Cincinnati Society of Natural History. 



%i. CioxiUM. Columella prominent, subcentral, globose. 

 obovoid, or turbinate ; the threads of the capillitium radi- 

 ating in all directions to the wall of the sporangium. 



A. Sporayi^ium stipitate. 



1. DiDYMiUM SQUAMULOSUM, A. & S. Sporangium vari- 

 able in form and size, small and globose, or large and much 

 depressed, the base usually umbilicate, stipitate, or sometimes 

 sessile, and even plasmodiocarp ; the wall very thin and 

 pellucid, with a thin, gray-white layer of stellate crystals of 

 lime, breaking up into subpersistent scales. Stipe short, 

 erect, snow-white, longitudinally furrowed or plicate ; the 

 columella central, snow-white, various in shape, globose, 

 obovoid, turbinate, and stipitate or sessile. Capillitium of 

 numerous colorless threads, radiating from the columella and 

 separating outwardly into several branches. Spores globose, 

 very minutely warted, dark violaceous, 8-10 mic. in diameter. 



Growing on old wood, leaves, herbaceous stems, etc. Spo- 

 rangium .4-. 6-. 8 mm. in diameter, the stipe scarcely longer 

 than the diameter, often much shorter or nearly wanting. 



2. DiDVMiUM PROXiMUM, B. & C. Sporangium globose or 

 depressed-globose, the base more or less umbilicate, stipitate; 

 the wall very thin and pellucid, with a loose white covering of 

 stellate crystals of lime, the upper part breaking up and falling 

 away. Stipe long, erect, tapering upward, yellow-brown to 

 reddish-brown, expanding at the base into a small hypothal- 

 lus ; the columella central, white, turbinate, or discoid turbi- 

 nate. Capillitium of slender, colorless threads, radiating 

 from the columella, branching and often anastomosing. 

 Spores globose, even, pale violaceous, 8-10 mic. in diameter. 

 Plate XII, Fig. 37. 



Growing on old leaves, sticks, culms, etc. Sporangium 

 .4-.6 mm. in diameter, the stipe two or three times the 

 diameter. 



3. DiDYMii'M KxiMii'M, Peck. Sporaugium depressed-glo- 

 bose, the base umbilicate, sometimes very much depressed 

 and also umbilicate above, stipitate; the wall pale ocher or 

 pale yellow, with a thin layer of minute white crystals of 



