KEYS TO THE MORE IMPORTANT GENERA OF FUNGI IMPERFECTI G21 



Conidia not in chains. 



Cells of the conidia not arranged in regular vertical rows. 



Conidia of irregular shape with irregular divisions; mostly rather short 



sessile. Coniothecium 



Conidia elongated, sessile or nearly so, on scanty mycelium, rather uniform 



in size and in manner of septation. Sporodesmium 



Conidia more or less ovoid, muriform, in little epiphyllous dense heaps. 



Stigmella 

 Cells of the conidium arranged in regular vertical rows which may separate 

 and spread at maturity. Speira 



Conidia in chains. Sirodesmium 



Conidiophores distinct, mostly erect. 



Spores obclavate, or attenuate at the distal end, borne singly or under favorable 



circumstances forming acrogenous chains. Alternaria^^ 

 Spores rounded at both ends, often sarciniform in appearance. 



Stemphylium'^'^ 



Key to the Scolecosporous Dematiaceae 



Conidiophores colored ; conidia lightly colored to almost hyaline ; never occurring 

 in chains; parasitic. Cercospora 



(closely related to Cercosporella) 

 Single genus. 



Key to the More Important Genera of Family Stilhellaceae^^ 



Conidia and conidiophores hyaline. 



Conidia one-celled, not in chains; synnema with a capitate sporogenous por- 

 tion, conidia embedded in a slime drop. Stilbella 



(Stilbum of many authors) 

 Conidia one-celled, not in chains; sporogenous portion of synnema cylindrical 

 or clavate; conidia not embedded in a slime drop. 



Isaria 

 Conidia one-celled; not in chains; synnema covered by numerous lateral 

 conidial heads; parasitic on insects (probably not properly placed in this 

 form family). Gibellula 



Conidia one-celled, produced in chains on more or less verticillate sterigmata 

 (phialides) ; in many cases merely cultural forms of Penicillium whose 

 conidiophores often are united into synnemata. 



Coremium 

 Conidia phragmosporous, straight, not in chains. Arthrosporium 

 Conidia phragmosporous, slender falcate, not in chains. 



Atradiujn 

 Conidia or conidiophores, or both, dark-colored. 

 Conidia one-celled. 



Conidia not in chains, globose, ellipsoid, or oval. 



2^ In mycological and pathological literature the name Alternaria is often reserved 

 for species occurring in chains and the genus Macrosporium for species never pro- 

 ducing chains. Sometimes the name Stemphylium is used in a manner synonymous 

 with Macrosporium. 



^' For helicosporous Stilbellaceae, see key on p. 611 for helicosporous Moniliales. 

 Many Moniliaceae and Dematiaceae under special cultural conditions will produce 

 coremia, e.g., Aspergillus, Penicillium, etc. 



