ON GRAMIXE.K 



263 



On Triticum vulgare. June — August. No secidium is known 

 to belong to it. (Fig. 200.) 



The Brown Rust of Wheat has been frequently so abundant in this 

 country in its uredo-stage as to cause great loss. The uredospores can be 

 distinguished from those of P. graminis, when both occur upon wheat, by 

 being subglobose, not elongate-ellipsoid, and by the more numerous germ- 

 pores which are scattered instead of forming an equatorial band ; also 

 they appear early in spring, before those of P. graminis. Sometimes the 

 teleuto-sori occur on the culms, and are then arranged more or less in 

 lines, but they are most common on the underside of the " flag " ; their 

 spores germinate only after a winter's rest. 

 Mesospores are not frequent in this species. 

 Klebahn tested the basidiospores of this 

 Rust on forty-two likely species of plants 

 in the hope of discovering an secidium in 

 its life-cycle, but without any result. The 

 uredospores were found to be capable of 

 surviving the winter by McAlpine in 

 Australia (where it is an introduced 

 species), and by Carleton in the United 

 States south of lat. 40° N. 



Fig. 200. P. triticina. 

 Teleutospores. 



(4) Puccinia holcina Erikss. 



Puccinia holcina Erikss. I.e. p. 274, pi. xiii, f. 22 — 5. Sydow, Monogr. 

 i. 715. Klebahn, I.e. p. 249. Fischer, Ured. Schweiz, p. 365. 



On Holcus lanatus, H. mollis. June — October. Common. 



The uredo-stage must be carefully distinguished from that of P. coronata, 

 which occurs on the same hosts ; the number of germ-pores at once decides 

 the question. The uredo-sori are of a brighter colour than in the other 

 forms of P. dispersa and stand upon conspicuous pale spots. The teleuto- 

 spores are more rarely produced and require to be looked for closely ; they 

 resemble those of P. triticina, but are mingled with a few mesospores. 



(5) Puccinia agropyrina Erikss. 



Puccinia agropyrina Erikss. I.e. [>. 273, pi. xii, f. 18 — 21. Klebahn, 

 I.e. p. 249. Sydow, Monogr. i. 712. Fischer, Ured. Schweiz, p. 365. 



On Agropyron caninum, A. repens. August — October. 

 (Fig. 201.) 



This is one of the commonest of the Rusts on wild grasses in the 

 autumn, and is easily recognised by the following points : The small 

 scattered dull-orange uredo-sori on the upper leaf-surface ; the round 

 faintly echinulate uredospores, which when empty show a pale-chocolate 



