PHRAGMIDIUM 



291 



The uredospores of this species are distinguished from those of its 

 allies by being densely and rather coarsely verruculose and very similar to 

 the Cccoma-spores, from which, in fact, they differ almost solely in being 

 abstricted singly and not in chains. The cseorna-stage is one of the earliest 

 Uredines of spring, showing on the leaves as soon as they are well 

 developed, and extending even to the calyx. The teleutospores are 

 entirely devoid of papilla on the apical cell ; the gelatinous outer coat 

 is sometimes almost non-existent, and the spores are but slightly changed 

 by boiling in lactic acid. 



Distribution : Europe. 



2. Phragmidium Potentillae Karst. 



Puccinia Potentillae Pers. Syn. p. 229. 



Phragmidium Potentillae Karst. Fung. fenn. iv. 49. Plowr. Ured. 



p. 221. Fischer, Ured. Schweiz, p. 410, f. 286. Sacc. Syll. vii. 



743. McAlpine, Rusts of Australia, p. 188 (?). Arthur, N. Amer. 



Fl. p. 174. Sydow, Monogr. iii. 97. 



Spermogones. Few, amphigenous, surrounded by the oecidia. 

 jEcidiospores. Cseomata as in P. Fragariastri. 



Fig. 220. Ph. Potentillae. a, teleutospore x 360 ; b, the same x 600; c, the 

 same, boiled in lactic acid for one minute ; d, a four-celled teleutospore, 

 boiled and distorted by pressure. 



Uredospores. Sori hypophyllous, roundish, often confluent, 

 at first covered by the swollen epidermis, surrounded by abun- 

 dant, clavate, curved paraphyses ; spores ellipsoid to obovate, 

 finely echinulate, yellow, 21 — 24 x 16 — 19 fi. 



Teleutospores. Sori hypophyllous, orbicular, soon naked, 



19—2 



