. The British rust fungi (Uredinales) their biology and classification. Rust fungi -- Great Britain. ON COMPOSITE 141. spores globose to ellipsoid, delicately echinulate, yellow-brown, 22—30 x 19—24 /j,, with two germ-pores. Teleutospores. Sori amphigenous and on the stems, scattered, minute, punctiform, pulverulent, blackish-brown; spores broadly ellip- soid, rounded at both ends, not thickened above, not constricted, very delicately verruculose, chestnut- brown, 30—35 x 22—27 //., sometimes longer ; pedicels hyaline, short. & t J Fig. 93. P. Cyani. On Centaurea Cyanus. Not un- Teleutospo
. The British rust fungi (Uredinales) their biology and classification. Rust fungi -- Great Britain. ON COMPOSITE 141. spores globose to ellipsoid, delicately echinulate, yellow-brown, 22—30 x 19—24 /j,, with two germ-pores. Teleutospores. Sori amphigenous and on the stems, scattered, minute, punctiform, pulverulent, blackish-brown; spores broadly ellip- soid, rounded at both ends, not thickened above, not constricted, very delicately verruculose, chestnut- brown, 30—35 x 22—27 //., sometimes longer ; pedicels hyaline, short. & t J Fig. 93. P. Cyani. On Centaurea Cyanus. Not un- Teleutospores. common in gardens. June—September. (Fig. 93.) There is a similar species, P. montana, which occurs on the continent on Centaurea montana ; it is distinguished by the much coarser warts of the teleutospores, which are also relatively longer. Both these species, like P. obtegens, permeate the whole plant with the mycelium of the primary uredospores, but such infested plants of Centaurea can flower freely, while those of Cirsiwm arvense never do. The mycelium of the secondary uredospores, mixed with teleutospores, is more strictly localised. Distribution : Western and Central Europe. 15. Puccinia Carduorum Jacky. Puccinia Hieracii Plowr. Ured. p. 185 , see also p. 216. P. Carduorum Jacky, p. 58. Sacc. Syll. xvi. 297. Sydow, Monogr. i. 33. Uredospores. Sori generally hypophyllous, on very indis- tinct spots, scattered, minute, pulverulent, cinnamon; spores globose or subglobose, densely echinulate, pale-brown, 22—28 p, with three germ-pores. Teleutospores. Sori similar, but dark-brown; spores variable, oblong to ovate, rounded above, not thickened, hardly at all constricted, rounded below, verruculose, brown, 25—38 x 17— 24 fx ; epispore thin ; pedicels hyaline, short. On Carduus crispus, G. nutans. Not common; Yorkshire, Clare Island, Please note that these images are extracted from scanned page images that may have been digitally e
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