390 



UREDINEAE. 



In ]\Iay or June the cushions swell up and become large 

 brownish-yellow gelatinous clumps, dotted over with dark points, 

 the teleutospores. Promycelia arise from one or more germ- 

 pores in each spore, and give off basidia with sporidia (basidio- 



HJ^>6WKfe.v, /^ I 



Fio. 224. — Accklia and Piiniidia of various species of GyninoKporanyhim : 



G. tremelloides — 1 and i', aecidia on leaf of Pi/rus Aria ; 5 and 6, aecidia on leaf 

 of Pyras Malus; 10 and 20, portions of the peridiuin of an aecidium from ii, 

 showing the peculiar articulation of the cells. 



G. juniperiiium — 3 and U, aecidia on Pyrus Aucuparia; 7 and S. aecidia on 

 Amelanchier vulgaris. 



0. clavariaeforme— 9 a.nd 10, aecidia on Pyius latifolia; 11, 12, and Hi, aecidia 

 on Crataegus Oxyacanlha, grown out-of-doors ; 7/,, the same aecidia, enlarged ; 

 l.i, I'l, and 17, aecidia on Crataegus Oxyacanlha, indoor culture; IS, deformed 

 twig of Crataegus bearing pycnidia. (After Tubeuf.) 



spores) capable of immediate germination. The gelatinous mass 

 dries up from time to time, leaving a bright yellow scar on 

 the swollen part of the host-branch. The sporidia germinate 

 most easily on species of Sorbiis (Fi/r/'s). Infections with 



