236 PUCCINIA 
above, scarcely or slightly thickened, gently constricted, rounded 
or attenuated below, smooth, brown, 28-—52 x 20—26 uw; pedicels 
hyaline, short, deciduous; mesospores numerous, obovate or 
pyriform, very irregular, 22—36 x 15—25 p. 
On leaves, sheaths and stems of various species of Allium, 
A. Cepa, A. Schoenoprasum, A. Scorodoprasum, etc. Rather 
uncommon. June—August. (Fig. 182.) 
Fischer describes the uredospores as pale-brown, distantly warted, 
28—82 x 21—28 p, and provided with three germ-pores. The ecidium on 
Allium which is usually placed with this species does not belong here. 
The ecidium on Allium ursinum is known to belong to one of the forms of 
P. sessilis : some, if not all, of the secidia on other species of Allium may 
be jn the same class. It was Tranzschel (Ann. Mycol. 1910, viii. 415) who 
proved that P. Porri is a Hemipuccinia ; he sowed the basidiospores on 
Allium and obtained the uredospores direct. The supposed ecidium 
is almost always found separate from the uredo- and teleutospores. There 
is a very close alliance between P. Porri and Uromyces ambiguus, if indeed 
they are not the two extremes of the same species. 
If this disease attacks cultivated onions, as it sometimes does, remove 
and burn all diseased plants and do not sow onions on the same ground 
again for several years. 
DistTRiBuTION: Europe, Syria. 
105. Puccinia obscura Schrot. 
Aeidium Compositarum var. Bellidis DC. ; Cooke, Handb. p. 543. 
Puccinia obscura Schrot. in Nuov. Giorn. Bot. Ital. ix. 256. Plowr. 
Ured. p. 174; Grevillea, xii. 86. Sacc. Syll. vii. 629. Sydow, 
Monogr. i. 645, 898. Fischer, Ured. Schweiz, p. 237, f. 187. 
Spermogones. Amphigenous, minute, in dense roundish 
clusters, honey-coloured. 
Aicidiospores. Aicidia amphigenous, on roundish or irregular 
yellow spots, in loose clusters or scattered, between cup-shaped 
and cylindrical, with whitish torn margin; spores delicately 
verruculose, yellowish, 16—22 p. 
Uredospores. Sori generally hypophyllous, on irregular 
confluent purplish-brown spots, scattered, elliptical or linear, 
long covered by the epidermis, pulverulent, rusty-yellow; 
