608 FUNGI IMPEKFECTi: THE IMPERFECT FUNGI 



Pycnidia ("pycnothyria") radial in structure, mounted on columellae whose 

 bases are connected with the internal mycelium. 



(Family Rhizothyriaceae, Tehon, 1940)^ 

 Conidia arising from the floor of the dimidiate subcuticular pycnidium. 



(Family Leptostromataceae) 

 Conidia one-celled, hyaline. 

 Stroma lacking. 



Pycnidia shield-shaped, opening by a pore or short slit. 



Leptothyrium 

 Pycnidia irregular in shape. Piggotia 



Pycnidia mostly oblong; opening by a long slit, 



Leptostroina 

 Stroma present (probably the conidial stage of Rhytisma). 



Melasmia 

 Conidia phragmosporous, hyaline, with a hair at each end. 



Discosia 

 Conidia hyaline, cruciform, with two large cells and usually two lateral cells, 

 all but the basal cell with a slender hair (conidial stage of Diplocarpon) . 



Entomosporium 

 Conidia muriform, hyaline. Didyosporium 



Conidia filiform, hyaline or nearly so. Leptosiromella 



Key to the More Important Genera of Family Excipulaceae^ 



Conidia globose, ellipsoid, oblong subcylindrical or fusoid, hyaline or only faintly 

 colored. 

 Pycnidia without hairs or bristles. 



Pycnidia eventually discoid; wall composed, at least in part, of modified host 



tissue. Discula 



Pycnidia eventually cup-shaped; walls of typical fungus tissue. 

 Pycnidia long buried, opening by laciniae. Sporonema 

 Pycnidia erumpent, opening by round pore. Excipula 

 Pycnidia erumpent, opening by a wide torn margin. 



Dothichiza 

 Pycnidia with setae. 



Conidia without appendages. Amerosporium 



Conidia with a delicate bristle at each end. Dinemasporium 



Conidia once septate; pycnidia opening by laciniae. Discella 

 Conidia oblong-fusoid, pluriseptate. 



Conidia hyaline; not prolonged into a subulate beak, pycnidia without bristles, 



Excipulina 

 Conidia colored; pycnidia with bristles. Excipularia 



Conidia hyaline; prolonged into a subulate beak; pycnidia without bristles. 



Heteropatella 



Asterostromella; (Hyalodidymae) Lepiothyriella; (Phaeodidymae) Diplopeltis. Tehon 

 recognizes ten other genera. 



* Tehon recognizes 6 genera of which Lindau, in Engler and Prantl includes in the 

 Leptostromataceae the following: (Hyalosporae) Aciinoihecium; (Phaeosporae) Piro- 

 stoma; (Scolecosporae) Actinothyrium. Besides these Tehon includes Piroslomella , 

 Rhizothyrium, and Cylindrolhyrium. 



' In some cases an old acervulus of Family Melanconiaceae may be mistaken for 

 the saucer-shaped pycnidium of the Excipulaceae. 



