CRYPTOGAMS 



193 



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

 ance of this Fungus in tlie spring tliat cue is at all likely 

 to see, however, is not upon a grass, 

 but on the leaves of the common 

 Barberry, in the form of tliick- 

 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 arc 



formed at the base 



of the chains while 



the terminal ones 



fall off and are 



carried by tlie winds to tlie Wheat (or 



other grass). The mycelium produced 



from these spores penetrates the body 



of the new host, 



where it increases 

 III] IP largely, working 



damage to the 

 md forni- 



h p 



31'J. Section tlironi;li a clus- 

 ter cup of Piici-inia in 

 the leat of llarberry. 



320. A stalk of grass 



with spores of Wheat, 



Puccinia break- . -, „ 



ma' at tlie surface 



ing through the 

 epidermis i 

 dark patches. 



masses of spores 



for the further 

 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 

 the spores are of two sorts (Fig. 

 321): (1) unicelkdar uredospores, 

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

 spread the l!us( l)y immediate germination on being Ijlowit 



OOT. OF EOT. 13 



Uredospnres and a te- 

 leiituspore (0 of Puc- 

 cinia. — De Baey. 



