. The British rust fungi (Uredinales) their biology and classification. Rust fungi -- Great Britain. 10 rKKlXlSPOKKS : Fig. 10. Leaf of Carex pendula, with uredo- and teleuto-sori, slightly en- larged. four)germ-pores; in tact, tin- uredo- resembles the aecidiospore in character, and musl b»- <-nsidered as homologous with it— the stalk-cell corresponding to the intercalary cell of the latter. But they differ considerably in the fad that the uredospore is always produced singly, uot in chains. (This is not true, however, of all the Uredinales.) The membrane of the uredosjxiiv is nearly colou
. The British rust fungi (Uredinales) their biology and classification. Rust fungi -- Great Britain. 10 rKKlXlSPOKKS : Fig. 10. Leaf of Carex pendula, with uredo- and teleuto-sori, slightly en- larged. four)germ-pores; in tact, tin- uredo- resembles the aecidiospore in character, and musl b»- <-nsidered as homologous with it— the stalk-cell corresponding to the intercalary cell of the latter. But they differ considerably in the fad that the uredospore is always produced singly, uot in chains. (This is not true, however, of all the Uredinales.) The membrane of the uredosjxiiv is nearly colourless, but it encloses a bright orange granular and oily mass, with two nuclei. Every cluster of uredospores produced on the same spore-bed is called a sorus; it is surrounded by the lacinise of the epi- dermis, which is more or less torn or split by the enlarging mass. In many cases, several sori become confluent and form a larger pustule (Fig. 10). In other species of Uredinales the uredospores have coloured membranes or possess a larger or smaller number of germ- pores. Moreover the distribution of these pores over the surface is characteristic for each species: they may be placed equatorially, as they are in P. Garicis (Fig. 11), or towards the poles, or scattered over the surface with regularity or without any order. A uredospore may be very easily detached from its pedicel, and conveyed (chiefly by wind, though sometimes by insects) to another leaf of Carex, on which it germinates, the germ-tube enters a stoma, produces a fresh crop of mycelium and another sorus of uredospores; this process can be repeated indefinitely. The my- celium can also grow up and down the leaf, producing fresh sori in its course; for this reason the sori are usually arranged in linear series, owing to the parallel venation of the Carex-leaf. The germ-tubes of the uredospores are often curled or branched like those of the ;ecidiospores, and the germination is of the same character in. Fig. 11.
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishercambr, bookyear1913
