192 



BOTANY. 



of the leaves of the Barberry. These cups are at first 

 rounded masses of conidia which develop on the internal 



FiQ. 113.— Wheat-rust (Puooinia graminia) . J, a cross-seotion of a Bar- 

 berry-leaf through a mass of cluster-cups ; o, n, a, cups opened and shed- 

 ding their conidia ; p, and A, above, cups not yet opened ; sp, sj), spermo- 

 gones which produce spermatia, whose function is not known. J/, three 

 Red-rust spores, ur, on stalks ; f, a Black-rust spore. III., a mass of Black- 

 rust spores bursting through the epidermis 6, of a leaf. All highly 

 maguifled. 



parasite, and at length burst through the epidermis (Fig. 

 113, A and /). The conidia quickly drop out and are car- 



