UREDINE^J. 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 yramlnis. A, part of a vertical section of a 

 leaf of the Barberry (Berberis vulgarix), with a young unopened .widium fruit ; '/. 

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

 from A toward y ; it, epidermis of the under surface ; o, of the upper "surface ; p, 

 unopened tecidinm fruit ; a, a, a, opened Kcidimu fruits ; sp, sp, spermagonia. II., 

 a mass of teleutospores on a leaf of Couch-grass* ( Triticum repens) ; e, tlie ruptured 

 epidermis ; 6. sub-epidermal fibres ol the grass leaf. ///., three uredospores, ur, 

 with one teleutosporu, t; sh. aub hymenial hyphaa. All highly m tgnifled. ^4 and /. 

 after Sachs ; II. and ///. after Be Bary. 



casionally these hyphae are found in other parenchymatous 

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

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



