. The British rust fungi (Uredinales) their biology and classification. Rust fungi. ON GEAMINEiE 259 On leaves, culms and glumes of Agropyron caninum, A. repens, Brachypodium sylvaticum, Bromus mollis and other species, Elymus arenarius, Hordeum vulgare, Secale Cereale,. Fig. 197. p. fflumarum. 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
. The British rust fungi (Uredinales) their biology and classification. Rust fungi. ON GEAMINEiE 259 On leaves, culms and glumes of Agropyron caninum, A. repens, Brachypodium sylvaticum, Bromus mollis and other species, Elymus arenarius, Hordeum vulgare, Secale Cereale,. Fig. 197. p. fflumarum. 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. Ruhigo-vera DO. ; 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 Eust on account of its early appearance, and Yellow Eust 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 a,s early as the beginning of May. The teleutosporos 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 belong to P. glumanum but has not yet been found i
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