1 86 British Urcdiuca: and Ustilao-inccr. 



Puccinia centaure^. Mart. 



Spennogonia — On yellow spots, which are round on the leaves, 

 elliptical or lanceolate on the petioles, where they are surrounded 

 by a purple margin. 



Uredospores — Primary : Sori few, surrounded by the spermogonia, 

 large, round or elliptical. Spores produced singly on basidia, 

 globose or subovate, echinulate, brown, about 25/^ across. 

 Secondary : Sori small, very numerous, scattered, mostly hypo- 

 phyllous, dark brown, soon pulverulent. Spores subglobose 

 or elliptical, brown, echinulate, 20-25 ^ 16-23/*. 



Teleutospores — Sori very small, amphigenous, roundish or oval, 

 black, pulverulent, often confluent. Spores elliptical, pyriform,, 

 or subglobose, not constricted, both cells equal or nearly so, 

 dark brown, smooth, 30-50 x 20-28/x. Pedicels hyaline., 

 short. 



Synonyms.. 



Puccinia centaurece. Mart., " Flor. Mosq.," p. 226. Cooke, 

 " Micro. Fungi," 4th edit., p. 207. Grev., "Flor. Edin.," p. 430. 



Puccinia compositar2im^ Mart., in part. Berk., " Eng. Flor,," 

 vol. V. p. 365. Johnst., "Flor. Berw.," vol. ii. p. 196. Cooke, 

 "Hdbk.," p. 499. 



Exsiccati. 



Vize, " Micro. Fungi Brit.," 120. 



On Centaiirea nigra. 



Biology. — The primary uredospores, accompanied by the spermo- 

 gonia, occur early in May, and are in very much larger sori than the 

 secondary uredospores. I found by experimental culture that the 

 primary uredospores produced the secondary in about fourteen days 

 (Exp. 851,852), but that no result followed when they were appUed 

 to Taraxacum officinale (853), Leofitodon autumnalis (923^ and 

 Hieracium pilosella (854, 855). 



Puccinia taraxaci. Plow. 



Spermogonia — On yellow oval or rounded spots. Paraphyses not 



conspicuous. Spermatia globose or oval, i-2yu, in diameter. 

 Uredospores — Primary : Sori scanty, large, dark brown, elongated 



