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 (Lascli.) (Britain). On Spiraea Filipendula. 

 T. echinatum Lev. occurs on Meum ; teleutospores alone are known 

 (U.S. AnuTica). 



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



Phragmidium. 



Teleutospores multicellular, the individual cells forming a 

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



Fig. 194. — Phrdf/riiidhim sitbcortichim 

 on a Rose leaf. The black spots are 

 teleutospore- patches on the under- 

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



Fl(j. 103. — TriphragnuuM ulmnriae on 

 Spiraea Uhiutna. Germinating teleuto- 

 spore, with proniycclia and sporidia. 

 (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 (Schr'ank.). Teleutospores, uredospores, and 

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

 America.) 



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

 (xviiiiw. 



Phr. fusiforme St-hrot. M'lu: rosae-alpinae (D.C.)]. On Rosa alpuia 

 (Britain). 



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



Phr. devastatrix Sor. On roses in Asia. 



' J. Miiller, " Die Rostpiize d. Rosa. u. Rubus-arten," Ber. d. 'detitsch. 

 botun. Ge-s., 188"). 



