THALLOPHYTA— FUNGI 



89 



easily transported by the wind. It is incapable of developing 

 a nncelium ujjon the grass, but if it falls upon the leaf of the 

 Barberry, it germinates, sending a hypha through the epidermis, 

 instead of penetrating a stoma like the uredospore. The myce- 

 hum resulting from this hypha forms a dense network in the inter- 

 cellular spaces of the leaf. At particular spots upon the leaf 

 brown pustules make their appearance, in which two kinds of 

 receptacles appear. Some on the upper surface of the leaf are 

 much like the spermogonia of the Ascomycetes, and bear the 



Fig. 851. 



Fig. 852. 



Fig. 851. Group of three uredospores, iu\ aud one teleutospore, t, springing 



from mycelium sh. Fig. 852. Section through leaf of the Barberry 



infested with Vuccinia graminis. o. Epidermis of upper surface of leaf. 

 sp. Spermogonia. p,p. Layers of cells {peridiuin), surrounding a, a, the 

 aecidium fruits. After Sachs. 



same name. They produce spermatia in the same way as the 

 latter. Upon the under surface large spherical bodies are formed 

 (fig. 852), containing a hymenial layer of sterigmata which 

 cut off from their apices a succession of spores known as 

 cEcidiosjJores, There are large numbers of chains of these thus 

 produced in the globular mass, which is known as an cEcidium 

 The whole secidium has a wall derived from the sterile hyphte 

 "When mature it ruptures and the spores escape. These are 

 . carried in their turn to other grass plants, and there germmatmg, 

 reproduce the uredo form, entering the grass through the stomata. 



