UREDINE^E. 



311 



hyphae, which penetrate between the cells, causing the leaves 

 to become usually much thickened and distorted in those 

 parts which are infested with the parasitic growths. Oc- 



Fig. 216. Several stages of Puccinia fframinis. A, part of a vertical section of a 

 leaf of the Barberry (Herberts vulgaris), with a young unopened iccidium fruit ; u. 

 epidermis. /., section of a Barberry leaf, natural thickness at X, greatly thickened 

 from h toward y ; u, epidermis of the under surface ; o, of the upper surface ; p, 

 unopened lecidium fruit ; a, a, a, opened uecidium fruits ; sp, fp, spennagonia. //.. 

 a mass of teleutospores on a leaf of Couch-grass (Tnticum repens) ; e, the ruptured 

 epidermis ; b, sub-epidermal fibres of the grass leaf. ///., three uredospores, ur, 

 with one teleutospore, t; gfi, sub-hymenial hyphie. All highly magnified. A and /. 

 after Sachg ; //. an J ///. after De Bary. 



casionally these hyphae are found in other parenchymatous 

 parts besides the leaves, as the petioles, young stems, and 

 even the flowers and traits. After a short time there form 



