260 puccixia 



122. Puccinia dispersa (sens, lat.) Er. ct Henn. 



Trichobasis Rubigo-vera L6v. ; Cooke, Micr. Fung. p. 222, pi. 7, 



f. 140- -2 , 

 Puccinia straminis Cooke, Micr. Fung. p. 202 p.p. 

 P. Rubigo-vera Plowr. Qred. p. Ui7 p.p. Sure. Syll. vii. 624 p.p. 

 /'. dispersa Erikss. et Eenning, Getreideroste, p. 210 L896 . Trans. 



Brit. Myc. Soc. i. 58. 



Uredospores. Sori generally epiphyllous or a few hypo- 

 phyllous, 1 — 2 mm. long, scattered without order, rarely con- 

 fluent, oblong or punctiform, rust-coloured or dirty-ochre, be- 

 coming paler; spores more or less globose, shortly echinulate, 

 dirty-yellow or dull-orange, 16 — 28 /x ; membrane distinctly 

 brownish (pale chocolate-umber) when mature; germ-pores 

 7 — 10, scattered over the whole surface. 



Teleutospores. Sori hypophyllous or less often on the 

 sheaths, scattered or slightly and irregularly aggregated, rarely 

 in distinct lines, small, oblong, covered by the epidermis, black : 

 spores oblong to clavate, truncate, rounded, or obtusely and 

 obliquely pointed above, slightly thickened, gently constricted, 

 narrowed downwards, smooth, brown, 35 — 56 x 12 — 23 fx: pedi- 

 cels short ; paraphyses numerous, brownish, more or less curved, 

 surrounding the spores. 



This is a general description of the forms included under the name 

 Brown Rust, to which the title P. dispersa was originally given. The 

 dirty-orange colour of the uredospores, which distinguishes them at a 

 glance from P. glumarum, is due to the fact that the membrane of the 

 spores is brownish, not hyaline ; the spore contents are orange in colour. 

 The germ -pores are scarcely perceptible in the immature or untreated 

 spore, but they can be seen easily if a spore is squeezed strongly between 

 the cover-glass and the slide, or by choosing a mature and empty spore. 

 In the teleutospores only the upper slightly thickened wall is dark- 

 chestnut, the rest being thin-walled and pale ; there is usually also a 

 chestnut-brown band at the apex of the pedicel. The structures called 

 paraphyses here in the teleuto-sori are quite different from those called by 

 the same name in Melampsora, etc. ; they are erect, coherent, thick- walled, 

 prismatic cells, which surround the teleuto-sori, or in the case of the 

 larger ones divide them into loculi. There are also paraphyses of the 

 ordinary shape, with a brownish membrane, mingled with the uredospores 

 in certain cases, but the occurrence of these seems, so far as is known at. 

 present, to be somewhat fortuitous. 



