320 



BOTANY. 



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

 the spore sends out apromycelium, 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 



FIG. 222. 



Flo. 223. 



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

 pha containing n row of young spores ; b, another spore-forming hypha, containing 

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

 brane of the hypha. X 1800. After Fischer von Waldheim. 



Fig. 222.- Snoie-formaiion in U#tilar/o anf/ierarum. a. an isolated gelatinous hy- 

 pha, with the'conteuts distinctly breaking up at the lower end a portion not yet 

 broken up ; b, annmber of gelatinous hyphte fused into an irregular mass, showing 

 the formation of nv>ny spores ; c, a spore nearly ripe, still surrounded by the gelat- 

 inous hypha membrane, also a voting cpore upon a lateral branch, a and c x 1800 ; 

 b X 900 After Fischer von Waldheim. 



Fig. 223. Formation of "solitary spores" in Sorispoi turn Saponarite. a, hyphm 

 with two young spores; 6, aspoie at a later stage; c, hyphre with spores in differ- 

 ent stages of development; at c' a thin wall has formed around the contained pro- 

 toplasm as in b ; at c" the wall is much thicker, and at c'" it is still thicker. 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 Waldheim, the germination of the fol- 

 lowing species is known, viz., Tilletia caries, T. Lolif, Ustilago an- 

 t/terarum, V. flnxculorum, U. carbo, U. destruens, U. Maydis, U. recep- 

 taculorum, U. longixsima, U. Vaittantii, Urocystis pompholygode*, 

 Uroc. occulta. 



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

 .!>< iriilia, he calls secondary sjwridia. 



