LITERATURE CITED 



427 



Teliospores mostly adhering in pairs. 



Agglntinated, in leaves. Schizonella 



Dusty, in inflorescences. Mycosyrinx 

 Teliospores in balls. 

 Sori dusty or granular. 



Spore balls often evanescent; olive-brown or black-brown. Sorosporium 



Spore balls rather permanent; yellowish or reddish. Thecaphora 

 Spore balls rather permanent; spores adhering by folds or thickenings of the 



outer coat. Tolyposporium 

 Sori agglutinated. 



Spore balls of thick-walled spores. Tolyposporella 



Spore balls of central sterile cells surrounded by the ])eripheral functional 



teliospores. Testicularia 



(It must be noted that Ustilago and Sphacelotheca are in some cases distin- 

 guished with difficulty. Furthermore, in some species of Sorosporium the telio- 

 spores do not remain adherent in the spore balls, so that they are not easily 

 distinguishable from the other genera. In some genera the germination of the 

 teliospores has not been studied, or perhaps in only a few species of the genus.) 



Key to the Commoner Genera of Family Tilletiaceae 



Teliospores single. 



Spores dusty and escaping at maturity. Tilletia 



Spores remaining embedded in the host tissue. Entyloma 



Teliospores in balls. 



Sori dusty ; spore balls more or less surrounded by an adhering layer of sterile 



cells; escaping from the ruptured sorus. Uroajstis 



Spore balls more or less permanently remaining in the host tissue. 

 Spore balls lacking a cortex of sterile hyphae. 



Spore balls dark, no sterile core. Tuhurcinia 



Spore balls light-colored, with or without a core of sterile pseudoparen- 



chymatous cells. Burrillia 



Spore balls light-colored, with a core of septate hyphae. Tracya 

 Spore balls with filamentous cortex. 



No central core of sterile cells. Doassansia 



A single layer of spores surrounding a large core of pseudoparenchymatous 

 cells. Doassansiopsis 



Key to the Genera of Family Graphiolaceae 



Bundles of sterile hyphae among the sporogenous hyphae; the latter separating at 

 maturity into their individual teliospores. Graphiola 



No bundles of sterile hyphae present; the sporogenous hyphae do not separate at 

 maturity into their individual teliospores. Stylina 



Literature Cited 



Adams, J. F.: Sexual fusions and development of the sexual organs in the Peri- 



dermiums, Penn. State Coll. Agr. Exp. Sta. Bull, 160:31-77. Pis. 1-5. Text 



Figs. 1-8. 1919. 

 Allen, Ruth F.: A cytological study of Puccinia glumarum on Bromus margin- 



atus and Triticum vulgare, J. Agr. Research, 36(6) :487-513. Pis. 1-12. 1928. 

 — — — ■: A cytological study of heterothallism in Puccinia graminis, ihid.. 40(7): 



585-614. Pis. 1-17. 1930. 



