90 



I'koMYCES 



e occurred for many years consecutively on Thrift in my garden, I 

 have never noticed the secidia ; the uredospores lasl through the winter 

 mi the evergreen leaves, and reproduce the Pungus about June; teleuto- 

 spores are rather scarce. 



Distribution: Central and North-Western Europe. 



5. Uromyces Trifolii LeV. 



Puccinia Trifolii Hedw. )'. in I"'. Flor. fr. ii. 225. 



Uromyces Trifolii Lev. Ann. Sci. Nat. ser. 3, viii. 371. Plowr. [Jred. 



p. 12 1 p.p. Sacc. Syll. vii. 534 p.p. Sydow, Monogr. ii. 132. 



Fischer, Ured. Schweiz, p. 23 p.p. 

 Trichobasis fallens Cooke, Micr. Fung. p. 226 p.p. 

 /',/.////,/ fallens Cooke, Handb. p. 508 p.p. 

 Nigredo fallens Arthur, X. Amer. Fl. vii. 2">4. 



Uredospores. Sori hypophyllous and on the petioles, 



and like those of U. Trifolii-repentis ; 

 spores differing in having 5 — 7 germ- 

 pores. 



Teleutospores. Indistinguishable from 

 those of U. Trifolii-repentis. 



On Trifolium hybridum, T. incarna- 

 f a in, T. medium, T. pratense. Not com- 

 mon. (Fig. 42.) 



Lire proved by culture-experiments that the Uromyces on Trifolium 

 repens could not be transferred to T. hybridum or T. pratense. Since this 

 difference is accompanied by the absence of the secidium in the latter 

 species and by a difference in the number of the germ-pores, they are 

 considered distinct by Sydow. But on Trifolium i>rntr, ise I have found 

 uredospores with not more than four germ-pores, each covered with a low- 

 hat hyaline cap. In that case only the absence of the secidium would 

 separate the two forms, though the average number of germ-pores is no 

 doubt different in the two cases. 



An secidium has been found elsewhere on T. pratense, but this has 

 been experimentally proved (Dietel, Flora, 189"), lxxxi. 398) to belong to 

 another European and North American species, U. minor Schrot. = U. ob- 

 longus Vize (Grevillea, v. 110), which has no uredospores, but only a'cidio- 

 and teleutospores. 



Cooke's species, U. apictdatus (Grevillea, vii. 136), is indefinite ; the 

 form on clover may belong here, that on Lathy rus prate asis to U. Pisi. 



1 Mstribution : Europe, Asia Minor, Persia, North America, 

 etc. 



Fig. 42. U. Trifolii. 

 Uredospores on T. 

 pratense. 



