344 



UREDINEAE. 



through the epidermis. The yellow uredospores are abjointed 

 singly fro'm long sporophores ; they are unicellular and ovoid, with 

 a thin granular coat beset with germ-pores (Fig. 184). The uredo- 

 spores are easily conveyed to other grass-plants and germinate at 

 once, their germ-tubes entering by a stoma and developing into 

 a mycelium, which can produce a new crop of uredospores in a 



FIG. 184. Puccinia gramiiiis. A, Portion of transverse section of leaf of Berlwis 

 viilgaris, with a young aecidium under the epidermis, v. 



I. Section through an aecidium-bearing spot of a Barberry leaf. At .c the 

 normal structure and thickness of the leaf is shown, the portion u to ?/ is 

 abnormally thickened ; h to o, upper surface of the leaf ; sp, pycnidia ; a, aecidia 

 in section ; p, their peridium. The aecidium marked p alone (without a) shows 

 a peridium exposed in surface-view only. 



II. Mature teleutospore-patch breaking through the epidermis, e, from the 

 tissue, /;. of a leaf of Triticum repens ; t, teleutospores. x 190. 



III. Teleutospores, t, and uredospores, ur. The teleutospore has a germ-pore 

 at its apex, the uredospores have four germ-pores at their equator. x 300. 

 (After De Bary, from Sach's Lehrbv.ch.) 



few days. The uredospores are summer-spores, and spread the 

 fungus during the vegetative period of the host-plant ; they may, 

 however, hibernate. The teleutospores are more suited for 

 hibernation; they are produced in autumn from dark brown 

 linear sori, distinguished from these of the uredospores by their 

 darker colour and greater length. The teleutospores are two-celled 

 and obovoid with smooth thick walls (Fig. 184); they are, like 



