ON WILLOW 343 



torn epidermis, orange ; spores roundish or subpolygonal, 18— 

 20x15 — 18 /x\ epispore about 3 p. thick, finely and densely 

 verruculose, with a few thinner places (? germ-pores). 



Uredospores. Sori mostly hypophyllous, on conspicuous 

 bright-yellow spots which show on both sides, \ — 1^ mm., 

 pulvinate, surrounded by the torn epidermis, bright orange-red ; 

 spores roundish, uniformly but not densely echinulate, 15—23 

 x 14 — 19 /x; epispore up to 2%fi thick, with a few thinner 

 places; paraphyses variable, capitate or clavate, 40 — 70 x 12— 

 21 fji, not thickened above. 



Teleutospores. Sori amphigenous, but mostly hypophyllous, 

 scattered or in little groups over the whole surface, subepider- 

 mal, small, I — \ mm. diam., brownish-black ; spores irregular, 

 prismatic, rounded at both ends, 25 — 35x7 — 10/x; epispore 

 thin, clear-brown, not thickened above, without evident germ- 

 pore. 



Casomata on Ribes alpinum, R. Grossularia (not on R. 

 nigrum, R. rubrum) ; uredo- and teleutospores on Salix pur- 

 purea. 



Description according to Fischer ; Klebahn's experiments have demon- 

 strated the connection of the parasites on these hosts. It is probable that 

 M. Ilibesii-auritae Kleb. is only a biological race of the same fungus, having 

 spermogones and cseoma-spores (according to Klebahn) on Ribes nigrum 

 as well as on the two mentioned above, and its other spore-forms on 

 Salve aurita and possibly S. Caprea. They are scarcely distinguishable, 

 if at all, morphologically ; both may be British. 



M. Larici-epitea is also recorded on >S'. purpurea, but can be distin- 

 guished by its densely clustered teleuto-sori on spots often bounded by 

 veins, and the paraphyses of the uredo-sori strongly thickened above. 

 M. mixta (Plowr. Ured. p. 239) may belong to either, but his species ex- 

 tended to the branches and inflorescence. 



6. Melampsora Orchidi-repentis Kleb. 



Uredo confluens var. Orchidia A. et S. Consp. p. 122. Cooke, Handb. 



p. 527. 

 U. Orchidis Mart. Flor. Mosq. p. 229. Cooke, Micr. Fung. p. 216. 

 Caeoma Orchidis Wint. Pilze, p. 256. Plowr. XTred. p. 261 ; Card. 



Chron. 1890, viii. 41. Saec. Syll. vii. 868. 

 Melampsora Orchidi-repentis Kleb. in Pringsh. Jahrb. f. Wissensch. 



Bot. 1900, xxxiv. 369. Fischer, Ured. Schweiz, p. 488. 



