. Les Britanniques rouilles (Uredinales), leur biologie et classification. Uredineae. Sur la gramine.* : 279 30-45x16-"22jx ; pédicelles courts, brunâtres, persistant ; à l'occasion, mésospore est trouvé.. Fig. 211. P. Poarum. Un iiredospore Teleutospores ;, sur P. nemoralis ; b, para- jihyses avec même ; c, mésospore ; &lt ;/, teleuto-sori sur P. 2}ratensis ; e-teleuto typique, sori de Uromijces Poae, sur le même. ^Ecidia sur Tussilago Farfar-a, à propos de Mai, Juin et Août, Septembre, très commune ; et teleutospores- uredo sur Poa annua, P. nemoralis, P. pratensis, P. trivialis, sur Juillet, août et octobre-Dece

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. The British rust fungi (Uredinales), their biology and classification. Uredineae. ON GRAMINE.*: 279 30—45x16—"22jx; pedicels short, brownish, persistent; an occasional mesospore is found.. Fig. 211. P. Poarum. Teleutospores; a, iiredospore on P. nemoralis; b, para- jihyses with same; c, mesospore; </, teleuto-sori on P. 2}ratensis; e, typical teleuto-sori of Uromijces Poae, on the same. ^Ecidia on Tussilago Farfar-a, about May, June, and August, September, very common; uredo- and teleutospores on Poa annua, P. nemoralis, P. pratensis, P. trivialis, about July, August and October—December, common but easily overlooked unless searched for. (Fig. 211.) First stated by Nielsen, the connection of the two hosts was demon- strated by Plowright and Ivlebahn. This heteroecious Puccinia differs from all others in having two generations in one year. The earlier crop of ajcidia begins to appear in May, and is followed by the uredo- and teleutospores on the surrounding leaves of Poa ; these germinate quickly and the second crop of tecidia is produced about August, and the second generation of teleutospores may be found on Poa from October. The latter germinate in the following spring, but according to Lagerheim the uredospores also, in a favourable climate, can survive the winter. This is certainly true in Australia, where (though the Puccinia is an introduced one) the uredospores have been found the whole year round. In that country the Coltsfoot does not exist, and the fungus is carried through the winter by the uredo-stage ; in fact, according to McAlpine, it is most common in the winter thei-e. Arthur and Carleton say that the fungus does the same as far north as Nebraska in North America, where the Coltsfoot is only a naturalised plant. Uredospores were found alive in every month of the year at Washington, D.C. In the Scottish Naturalist ('84, p. 270) this species is recorded for Poa fluitans, but there may possibly be some error in this statement. Plow- rig

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