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 Spirufi Filipendula. 

 T. echinatum Lev. occurs on Maim teleutospores alone are known 

 (U.S. America). 



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



Phragmidium. 



Teleutospores multicellular, the individual cells forming a 

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



FlG. 194. Phrii'ini "li Hni xubcni't'ii-'' I* in 

 on a Rose leaf. The black spots are 

 teleutospore - patches on the uuder- 

 surface of the leaf. (v. Tubeuf del.) 



FIG. 1513. Triphmgmium ulmurim <>ii 

 Spiraea Ulmaria. Germinating teleuto- 

 spore, with promycelia and sporidia. 

 (After Tulasue.) 



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 Rosa, : 1 



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

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

 America.) 



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

 i-ii HI/HI. 



Phr. fusiforme Schrot. [I'/u: rosae-alpinae (D.C.)]. On Rosa alpina 

 (Britain). 



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



Phr. devastatrix Sor. On roses in Asia. 



1 J. Miiller, " Die Rostpilze d. Rosa. u. Rubus-arten," Ber. d. dtut*<-h. 

 botan. Ge>s., 1885. 



