320 



BOTANY. 



for a few species only. * In all which have been examinea 

 the spore sends out a promycelium, which is generally short 

 and jointed, and upon this several sporidia are produced, 

 much as in the Uredineae. In Tilletia caries the promyce- 

 lium produces a tuft of slender branches (Fig. 224, h), which 



a 



Fjg. S81. Fig. 222. Fio. 23.3. 



Fig. 221.— Spore-formation in Ustilago MaydU. a, the end of a spore-forming hy- 

 pha containing il row of young spores ; 6, anotlier spore-forming llypha, containing 

 two young spores ; c, a spore nearly ripe, still burrounderl by the gelatinous mem- 

 brane of the hypha. X 1800.— After Fischer von Waldtieim. 



Fig. 222.— Spore-formation in Ustilago antlurarufn. a. an isoia.'-<' gelatinous hy- 

 pha, witti the contents distinctly breaiiing up — at the lower end a portion not yet 

 broken up ; 6, anumber of gelatinous hyphie fused into an irregular mass, showmg 

 tlie formation of many spores : e,'a spore nearly ripe, still surrounded by the gelat- 

 inous hyplia membrane, also a young spore upon a lateral branch, -a and c X 1800 ; 

 6 X 900. — After Fischer vou Waldheim. 



Fig. 223. — Formation of "solitary spores" in Sonspoiium. Saponarice. a, hyphse 

 "wltti two young spores; b, aspoie at a later stage; c, hyphse with spores in differ- 

 ent stages of development ; at c' a ttiin wail has formed around tlie contained pro- 

 toplasm as iu 6 ; at c" the wall is much thicker, and at c'" it is still thiclter. X 300. — 

 After De Bary. 



have been seen to unite laterally by a kind of conjugation 



' (not, however, of a sexual nature, in all probability) ; from 



these branches (called by some writers " secondary spores ")f 



* According to Fischer von Waldlieim, the germination of the fol- 

 lowing; species is known, viz., IWetia caries, T. Lolii, Ustilago an- 

 therarum, U. flosculorum, U. carbo, IT. destruens, U. Maydis, U. recep- 

 taculorwm, U. longisdma, U. Vaillantii, Uroeystis pompholygodes. 

 Uroc. occulta. 



f De Bary calls these branches sporidia, and what are here called 

 sporidia, he calls secondary sporidia. 



