362 



UREDINEAE. 



points. The so-called aecidia are really a form of uredo-sori; 

 they occur as thick cushions and cause thickening or twisting 

 of the leaves and petioles. 



T. filipendulae (Lasch.) (Britain). On Spiraea FUipendula. 

 T. echinatiun L6v. occurs on Meum ; teleutospores alone are known 

 (U.S. America). 



T. clavellosum Berk. On leaves of Aralia in the United States. 



Phragfmidium. 



Teleutospores multicellular, the individual cells forming a 

 single series ; they show a variable number of germ-pores. The 



FiG. 194. — PhrftgniidiiiTn sttbcwticium 

 on a Rose leaf. The black spots are 

 teleutospore- patches on the uuder- 

 surface of the leaf. (v. Tubeuf deL) 



Fig. 193. — Tfipkragmium ulmai-iac on 

 Spiraea Ulmai-ia. Germinating teleuto- 

 spore, with promycelia and ^poridia. 

 (After Tulasne.) 



teleutospores are produced in loose patches. The aecidial patches 

 have no covering, but are surrounded by club-shaped paraphyses. 



The genus frequents only Eosaceae. 



On species of Bosa : ^ 



Phragmidium subcorticium (Sclirank.). Teleutospores, uredospores, and 

 aecidia on leaves of wild and cultivated roses. (Britain and U.S. 

 America.) 



Phr. tuberculatum J. Mull. All the forms of spore occur on Rosa 

 canina. 



Phr. fusiforme Schrbt. \Phr. rosae-alpinae (D.C.)]. On Rosa alpiiia 

 (Britain). 



Phr. speciosum (Fr.). On North American roses. 



Phr. devastatrix Sor. On roses in Asia. 



' J. Miiller, " Die Rostpilze d. Rosa. u. Kubus-arten," Ber. d. denisch. 

 botan. Ges., 1885. 



