THE FAUNA OF BOULDER COUNTY 233 



(17) Fuligo Haller. Fructification compound, called an aethalium. Large convex 

 masses, up to 20 cm. broad, varying from pale yellow to red and brown. 

 F. septica (Linn). 



(18) Crateriiim Trentepohl. Sporangia in the shape of a covered goblet, the 

 stalks cartilaginoid. On dead leaves and twigs. 



C. leticocephalmn (Pers.), sporangia, red-brown, white and mealy, with sprinkled 

 yellow granules on upper half and lid; C. minutiwi (Leers), sporangia smooth, 

 with a pale lid. 



Family DIDERMIDiE 

 Capillitium without lime. 



(19) Diderma Persoon. Sporangium wall opaque, of two layers, containing 

 granular deposits of lime. Diderma proper, including in our fauna D. spumari- 

 oides Fries and D. globostim Pers., has the outer sporangial wall distinctly cal- 

 careous, fragile. The subgenus Leangium, of which we have D. trevelyani (Grev.) 

 and D. stellare (Schrad.), has the outer sporangial wall cartilaginoid, the inner less 

 distinct, or not separable from the outer. D. trevelyani is chestnut-brown. 



(20) Diachaea Fries. Sporangium wall hyaline, the lime confined to the stalk 

 and columella. D. leucopoda (Bull.). 



Order DIDYMIACEM 



Lime in crystals deposited outside the sporangium wall (Lister). 

 Family DIDYMIIDiE 



(21) Didymium Schrader. Fructification simple; sporangium wall membranous; 

 crystals stellate. D. farinaceum Schrad.; D. squamiilosum (Alb. and Schw.); 



D. anellus Morg.; D. nigripes (Link.), var. eximium (Pk.). 



(22) Spumaria Persoon. Fructification compound, the sporangia forming an 

 aethahum. Very variable; on grass, shrubby plants, etc. 



5. alba (Bull.) and var. solida Sturgis. 



Macbride considers that Spumaria should be called Mucilago Adans., and 5. alba 



becomes Mucilago spongiosa (Leyss.). 



Order STEMONITACEM 



Sporangia distinct, without lime, provided with a stalk and columella. (The 

 columella is the axis of the stalk prolonged upward into the sporangium.) 



Family STEMONITID^ 



Sporangium wall evanescent. (In Lamprodermatidae it is more or less persistent.) 



(23) Stemonitis Gleditsch. Sporangia cylindrical; capillitium forming a net at 

 surface. The following key separates the Boulder County forms: 



Spores grey, violet-grey or rufous violet. 



Spores reticulated; sporangia dark or reddish brown, 4 to 15 mm. high 



fusca Roth. 

 Spores minutely warted, almost smooth. 



Meshes of surface net rounded, 20-100 m or more wide splendens Rost. 

 Meshes of surface net angular, less than 20 /a wide . herbatica Peck. 



