. The British rust fungi (Uredinales) their biology and classification. Rust fungi. 170 PUCCINIA. Pif!. 120. P. Veronicarum. Te- leutospores on V. alpina (ex herb. Berkeley). compact, pulvinate and greyish, others brown and pulverulent; spores oblong or obovate, attenu- ated into a horny much thickened (up to 8 fj,') conical point at the apex, constricted, slightly tapering below, smooth, pale or dark chest- nut-brown, 28—40x14—19^; pedicels hyaline or somewhat yel- lowish, rather long, deciduous or persistent. On Veronica alpina, V. offici- nalis and perhaps other species. Not common. July—Oc
. The British rust fungi (Uredinales) their biology and classification. Rust fungi. 170 PUCCINIA. Pif!. 120. P. Veronicarum. Te- leutospores on V. alpina (ex herb. Berkeley). compact, pulvinate and greyish, others brown and pulverulent; spores oblong or obovate, attenu- ated into a horny much thickened (up to 8 fj,') conical point at the apex, constricted, slightly tapering below, smooth, pale or dark chest- nut-brown, 28—40x14—19^; pedicels hyaline or somewhat yel- lowish, rather long, deciduous or persistent. On Veronica alpina, V. offici- nalis and perhaps other species. Not common. July—October. (Fig. 120.) There are two forms of spores in this species ; one, fragilipes, with deciduous pedicels ; the other, persistens, with persistent pedicels. In the former, the sori are soon naked and pulverulent, the spore-wall is thicker and darker-coloured, and germination takes place only after a winter's rest. In the latter, the sori are compact, the spores are thin-walled and paler and germinate as soon as mature, upon the living plant. But occasionally both forms may be seen in the same sorus. It is the latter form that spreads the parasite during the summer; the former causes new infections in the following spring. Distinguished from F. Veronicae by the relatively broader spores, and the cone-shaped apical thickening. It is possible that the Pucciniae on other species of Veronica, included by the Sydows with this, are really distinct. But in Herb. Berkeley there is a Puccinia on Veronica alpina, from Ben Aulder, Invernessshire (and also from Perthshire) which is undoubtedly this species. The sori are hj'pophyllous only, but cover the larger part of each leaf. The spores are quite smooth, by which it is distinguished from the continental form on V. alpina, which has the upper spore-cell occasionally warted on the upper part; this form {P. albulensis Magn.) has the sori densely gregarious on stems as well as leaves, some- times covering a whole internode. DiSTKiBUT
Size: 1795px × 1393px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookpublishercambr, bookyear1913
