. The British rust fungi (Uredinales) their biology and classification. Rust fungi. ON GERANIACE^ 105 by a pore; spores roundish-polygonal to oblong-ovate, densely verruculose, yellow, 24—33 x 18—26 ytt. Uredospores. Sori hypophyllous, on yellow spots, in circi- nate groups, seldom scattered, rather large, pulverulent, choco- late-brown ; spores roundish, brown, distantly echinulate, 22— 26 fi; epispore about 2 /j, thick. Teleutospores. Sori hypophyllous, on yellowish or reddish. Fig. 58. U. Kabatianus. Teleutospores and uredospore, on G. pyrenaicum. spots, rather large, covered with the thin
. The British rust fungi (Uredinales) their biology and classification. Rust fungi. ON GERANIACE^ 105 by a pore; spores roundish-polygonal to oblong-ovate, densely verruculose, yellow, 24—33 x 18—26 ytt. Uredospores. Sori hypophyllous, on yellow spots, in circi- nate groups, seldom scattered, rather large, pulverulent, choco- late-brown ; spores roundish, brown, distantly echinulate, 22— 26 fi; epispore about 2 /j, thick. Teleutospores. Sori hypophyllous, on yellowish or reddish. Fig. 58. U. Kabatianus. Teleutospores and uredospore, on G. pyrenaicum. spots, rather large, covered with the thin silvery-shining epi- dermis, generally in circinate groups, soon confluent, pulverulent, brown; spores ovate, often oblong, scarcely thickened above, . but with the germ-pore provided with a prominent subhyaline papilla (up to 7 /u, high), smooth, pale-brown, 22—42 x 13—20 /x; pedicels short, hyaline, deciduous. On Geranium pyrenaicum, and possibly on G. molle and G. piisillum. (Fig. 58.) This has been separated by Bub^k from U. Qeranii on the ground of the circinate arrangement of the uredo- and teleuto-sori, and the more oblong and longer teleutospores : the description of the secidia and teleu- tospores is taken from that of Bubdk. According to Sydow, Lind has succeeded in transferring this species from O. pyrenaicum to O. molle and G. pudllum. Bub4k thought that only this form occurred on G. pyrenai- cum, but Book (Centralbl. f. Bakt. 2, xx. 584) showed that typical Uromyces Qeranii could also be produced on that host. The two Uromyces are very closely allied, but several distinctions are alleged: the uredospores themselves are identical, but not the sori; according to Sydow, the teleutospores of U. Kabatianus do not appear till towards the end of October, are paler, longer and more oblong in shape with a higher papilla, while their sori are generally circinate, paler and less compact. The teleutospores of U. Qeranii appear at the beginning of summer, the sori are
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