KEYS TO THE MORE IMPORTANT GENERA OF FUNGI IMPERFECTI 607 



Conidia slender, many times as long as thick, more often hyaline or only slightly 



colored, with or without cross septa. 



Scolecosporae 

 Without stroma. 



Pycnidia tapering upward to a point; carbonaceous. 



Conidia filiform, one-celled. Sphaerographium 



Conidia several-celled, constricted at each septum. 



Cornularia 

 Pycnidia globose to depressed globose, ostiole at most with a small papilla; 



carbonaceous. * 



Pycnidia opening by a rather small round ostiole. 



Pycnidia more or less sunken in the host tissue, emergent somewhat at 

 maturity. 

 Pycnidia glabrous; parasitic in leaves or herbaceous stems. 

 Conidia hyaline or at most light-colored. 



Septoria 

 Conidia distinctly brown. Phaeoseptoria 



Pycnidia glabrous; growing on wood or bark. 



Rhabdospora 

 Pycnidia hairy. Trichoseptoria 



Pycnidia superficial; conidia straight, cylindrical, or narrowly fusoid. 



Collonema 

 Pycnidia opening by a wide mouth; not completely developed. 



Phleospora 

 Pycnidia opening by a narrow slit; not completely developed. 



Phlyctaena 

 Pycnidia globose-conical; tough or leathery. 



Pycnidia separate. Micula 



Pycnidia crowded in heaps. Micropera 



With stroma. 



Conidia hyaline, filiform, curved, one-celled. Cytosporina 

 Conidia dark, several-celled. Septosporiella 



Key to the Important Genera of Family Zythiaceae 



Stroma lacking; pycnidia globose, with small ostiole, conidia ovoid or oblong, 



resembling the perithecia of Nectria. Zythia 



With a cushion-like stroma containing several pycnidial cavities; superficial, 



parasitic in some cases on leaf-sucking insects. Aschersonia 



Key to the More Important Genera of Family Leptostromataceae 



(Including the Pycnothyriaceae and Rhizothyriaceae, Tehon, 1940) 



Conidia arising from the roof of the external pycnidium. 



(Order Pycnothyriales, Tehon, 1940) 

 Pycnidia ("pycnothyria") radial in structure, often connected with an external 

 mycelium or subiculum. 



(Family Pycnothyriaceae, von Hohnel, 1910)^ 



' Tehon recognizes 15 genera, with probably not over 40 described species, mostly 



tropical or subtropical. The following are included in Leptostromataceae by Lindau, 



n Engler and Prantl: (Hyalosporae) Eriothyrium, Trichopeltulum; (Phaeosporae) 



