. The British rust fungi (Uredinales) their biology and classification. Rust fungi -- Great Britain. ON 259 On leaves, culms and glumes of Agropyron caninum, A. re pens, Brachypodium sylvaticum, Bromus mollis and other species, Elymus arenarius, Hordeum vulgare, Secede Cereule, I). ;.<•• ..*' / : a b1. Fig. 197. P. glumarum. a, uredo-sori and b, teleuto-sori, on leaves, nat. size ; c, teleuto-sori, on glume ; d, uredospore ; e, teleutospore. Triticum vulgare. It is one of the few species that attack the ears, to which it does serious damage. (Fig. 197.) This is one of two forms or
. The British rust fungi (Uredinales) their biology and classification. Rust fungi -- Great Britain. ON 259 On leaves, culms and glumes of Agropyron caninum, A. re pens, Brachypodium sylvaticum, Bromus mollis and other species, Elymus arenarius, Hordeum vulgare, Secede Cereule, I). ;.<•• ..*' / : a b1. Fig. 197. P. glumarum. a, uredo-sori and b, teleuto-sori, on leaves, nat. size ; c, teleuto-sori, on glume ; d, uredospore ; e, teleutospore. Triticum vulgare. It is one of the few species that attack the ears, to which it does serious damage. (Fig. 197.) This is one of two forms originally included under the collective name P. Rubigo-vera DC. ; they can best be distinguished in the uredo-stage. In the one, P. glumarum, the uredo-sori are abundant, clear lemon- or sometimes orange-yellow, and stand in long lines, often occupying half the leaf-blade ; in the other, P. dispersa and its subordinate forms, they tend towards brownish-orange or even chocolate-brown, and are scattered, rather thinly and without order, over the whole leaf-surface. Eriksson and Henning first proved in 1896 what had been long surmised, that they are quite distinct. P. glumarum has no known secidial form, and has been divided into five biological races (see p. 67). It is common in certain districts of England and is called the Spring Rust on account of its early appearance, and Yellow Rust on account of its bright colour, which varies from sulphur- to pale cadmium-yellow. The lines of the uredo-sori may be as much as 7 cm. long, chiefly on the upper face of the leaf; they can be found all the year round on suitable leaves, and are frequently abundant on Wheat as early as the beginning of May. The teleutospores germinate as soon as they are mature ; the basidium is yellow until the basidiospores are formed, not colourless as in P. dispersa. On Hordeum murinum there is recorded a form, P. Hordei Fckl., which has smaller yellow sori, arranged less evidently in lines ; this may belo
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