. The British rust fungi (Uredinales) their biology and classification. Rust fungi -- Great Britain. Fig. 94. P. Cirsii. Teleuto- spores, on C. palustre, from Hereford. Fig. 95. P. Cirsii. Teleuto- spore and uredospore, on G. lanceolatum. Teleutospores. Sori mostly hypophyllous only, similar, but blackish-brown or black ; spores ellipsoid or somewhat obovate, rounded at both ends, not thickened above, hardly constricted, verruculose or merely punctate, chestnut-brown, 25—38 x 17—25/it; epispore thin; pedicels hyaline, very short. On Cirsium, Dupplin Castle, Perth (M. C. Cooke). On G. pratense,


. The British rust fungi (Uredinales) their biology and classification. Rust fungi -- Great Britain. Fig. 94. P. Cirsii. Teleuto- spores, on C. palustre, from Hereford. Fig. 95. P. Cirsii. Teleuto- spore and uredospore, on G. lanceolatum. Teleutospores. Sori mostly hypophyllous only, similar, but blackish-brown or black ; spores ellipsoid or somewhat obovate, rounded at both ends, not thickened above, hardly constricted, verruculose or merely punctate, chestnut-brown, 25—38 x 17—25/it; epispore thin; pedicels hyaline, very short. On Cirsium, Dupplin Castle, Perth (M. C. Cooke). On G. pratense, Ballyquirke Lake, Co. Gal way (communicated by J. Adams); Earlswood Lakes, near Birmingham. On G. palustre, Hereford, Seckley Wood, Barnt Green, etc. Uredospores from March ; teleutospores, June—November. (Figs. 94, 95.) There is no mention of this in Plowright's Uredinese, or in the Trans. Brit. Myc. Soc. (Plowright's list), but it is probably not uncommon. It occurs frequently on the radical leaves, and can be easily distinguished from P. Cnici-oleracei by the presence of the uredospores and the non- circinate teleuto-sori, as well as by the absence of the apical thickening. Fischer records it from Switzerland on many species of Cirsium (but not on those mentioned here), and also assigns to it sperrnogones on the upper leaf-surface and petiole ; I have not been able to find any trace of these in our British specimens. The uredospores, seen in water, sometimes appear quite smooth, as Cooke describes them. The teleutospores have the upper pore at the summit or at the side, the lower pore just beneath the septum or lower down ; they are at times faintly granulated, at others distinctly verruculose. Mesospores are rare. I have also a number of specimens on C. lanceolatum from Droitwich, Wyre Forest, etc., bearing a great similarity to P. Cirsii-lanceolati Schrbt., but the differences from P. Cirsii are so slight and elusive that, as the secidial stage by which the former i


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