292 



l'llltAC.MIDIIM 



black; spores cylindrical or subclavate, of 3 6 cells (occasionally 

 one or two), rounded or bluntly papillate at the apex, hardly 

 constricted, smooth, brown, 42 — <S0 x 20 — 'IH/x: two or three 

 germ-pores to each cell: pedicels thick, hyaline, persistent, as 

 long as or much longer than the spores (100 — loO/x). 



On Potentilla argentea, P. verna, and various cultivated 

 species. April — September. Not common. (Fig. 220.) 



This species is more closely allied to /'. Sanguisorbae than to 

 /'. Fragariastri. The finely echinulate uredospores and the papillate 

 teleutospores distinguish it from the latter. 



DISTRIBUTION : Europe, Asia Minor, Siberia, Japan, North 

 America, Australia (?). 



3. Phragmidium Sanguisorbae Schrbt. 



Pucdnia Sanguisorbae DC. Flor. fr. vi. 54. 



Lecytkea Poterii Lev. ; Cooke, Micr. Fung. p. 221, pi. 3, f. 31. 

 Phragmidium Sanguisorbae Schrot. Flor. Schles. p. 352. Plowr. Ured. 



p. 221. Fischer, Ured. Schweiz, p. 408, f. 285. Sacc. Syll. vii. 



742. Sydow, Monogr. iii. 156. 

 P. acuminatum Fr. ; Cooke, Handb. p. 490 ; Micr. Fung. p. 201, pi. 3, 



f. 30, 32. 



Spermogones. Amphigenous, flat, clustered. 



jEcidiospores. Caeoinata amphigenous, oblong, circinate 



round the spermogones, or irregular 

 and swollen on the nerves and petioles ; 

 spores verruculose, orange-yellow, 18 — 

 21 fi : paraphyses curved. 



Uredospores. Sori small, scarcely 

 \ mm., soon naked, surrounded by a 

 circle of clavate, curved paraphyses; 

 spores globose to ovate, echinulate, 

 orange-yellow, 18 — 24 /u.. 



Teleutospores. Sori punctiform, \ — 

 1 mm., soon naked, black : spores cylin- 

 drical-oblong, of 2 — 5 (mostly four) cells, 

 apex drawn out into a papillate beak. 



faintly constricted, base rounded, some- 

 a, telentospore x 360 ; h. J 



teleutospore x 600. what verruculose, j^ellowish-brown, 56 — 



