SECT. I 



CRYPTOGAMS 



105 



Thus Tilldia, unlike Usfilago, produces conidia of two forms ; but in other 

 particulars the development of both groups is the same. 



The young resting-spores and the cells of the mycelium from which they are 

 produced contain each two nuclei which fuse with one another as the spore becomes 



Fig. 33S. — I'uccinia ijraiainis. 1, Transverse-section tliroii.Lili a grass-hanlm witli group of teleuto- 

 spores ; 2, germinating teleutospore with two basidia ; ■!, vegetative, -i, fructifying germinating 

 basidiospore ; tlie lattei* has formed a' secondary spore, not having been able to infect a host 

 plant ; n, a portion of a group of uredospores (u) and teleutospores (0 ; p, the germ-spores ; C, 

 germinating uredospore. (/, 2, 3, k, after Tulasne ; .5, 6, after De B.arv ; 1 x 150, i x circa 

 230, 3, 4 X sro, 5 X 300, X 390, from v. Tavel, Filze.-) 



mature. The cells of the basidia, and the basidiospores are all uninucleate, only 

 the secondary conidia of Tilletia being again biuucleate. 



Order 2. Uredineae (Rust-Fungi) {^^'^^) 



The mycelium of the Uredineae lives parasitically in the intercellular spaces of 

 the tissues of the higher plants, especially in the leaves, and gives rise to the 



