CRYPTOGAMS 



193 



Rye, Oats, and various other grasses. The first appear- 

 ance of this Fungus in the spring that one is at all likely 

 to see, however, is not upon a grass, 

 but 011 the leaves of the common 

 Barberry, in the form of thick- 

 ened red patches. On the under 

 side of these areas, embedded in 

 the leaf tissues, are then found the 

 so-called cluster cups, or fructifica- 

 tions (Fig. 319), 



filled with chains 



of rounded spores. 



New spores are 



formed at the base 



of the chains while 



the terminal ones 



fall off and are 



carried by the winds to the Wheat (or 



other grass). The mycelium produced 



from these spores penetrates the body 



of the new host, 



where it increases 



largely, working 



320. A stalk of grass damage to the 

 with spores of Wheat, and form- 



Puccinia break- . .-, f 



ing through the m g at tne surface 

 masses of spores 

 for the further 



319. Section through a clus- 

 ter cup of Puccinia in 

 the leaf of Barberry. 



epidermis in 

 dark patches. 



spread of the disease. The spores 

 produced on the Wheat are differ- 

 ent both in shape and in the manner 

 in which they are borne from the 

 spores of the cluster-cup stage on 



Barberry. Moreover, on Wheat 32L Uredospores and a te - 

 the spores are of two sorts (Fig. 

 321): (1) unicellular uredospores, 

 prevailing until late summer or fall, the office of which is to 

 spread the Rust by immediate germination on being blows- 



OUT. OF BOT. 13 



leutospore () of Puc- 

 cinia. DE BARY. 



