UREDINE^E. 



315 



Fig. 219. Youne teleuta- 

 spores of Phragmidium mu- 



ture follow or proceed from a sexual act ; and maintains that the aecid. 

 ium fruit is more complex in structure than any of the others. He 

 further says, " The aecidium fruit corresponds, then, to the perithecium of 

 the Ascoinycetes, the secidiospores to the ascospores ; and the uredo- 

 spores and teleutospores are evidently differ- 

 ent forms of conidia." It is very doubtful, 

 however, whether future investigations will 

 prove the correctness of Sachs' surmise. It is 

 much more probable that the teleutospores re- 

 sult from a sexual act, and that they are to 

 be compared to the asci of the Ascomycetes. 

 The teleutospores are possibly reduced asci, 

 containing one or more large ascospores ; in 

 some cases e.g., in Puccinia Helianthi an 

 outer investing membrane can be distinguish- crondtum, showing tiie an 



eH nttr treatment witli r>nt<5ip livrlrntp glllar masses which eventu- 



Lle ally develop Into the cells 

 while in Puccinia ( Uropyxis) Amorphce there of the mature teleutospore. 



is "a deciduous outer coat,"* which contains Highly ma g nifled - 

 the double spore, and (when moistened) a mass of jelly. In both these 

 cases the membranous covering closely resembles an ascus which fits 

 closely over its contained double spore. In the genus Phragmidium 

 (Fig. 220), especially in young teleutospores, the resemblance to asci 

 and ascospores is still more striking ; the so- 

 called " cells" of the teleutospore originate as so 

 many separate masses in the interior of a large 

 ascus-like membrane (Fig. 219) ; in their further 

 development the cells become large, and at last 

 fill up the whole cavity, and then have the ap- 

 pearance of Fig. 220. 



The resemblance of the teleutospores to re- 

 duced asci is close enough to make it probable 

 that sexual organs resembling those of Asco- 

 mycetes will be found to precede them. This 

 is rendered the more probable from the resem 

 blance of secidiospores, spermatia, and uredo- 

 spores to the conidia, spermatia, and stylospores 

 of various Ascomycetous fungi. f 



(d) The principal genera in this order are 

 Uromyces and Melampsora with one-celled te- 

 leutospores, Puccinia and Gyrmiosporangium, 

 with two cells, and Phragmidium (Fig. 220) with 

 many cells. Many species are known, there being in the genus Puo 



* So described by Berkeley : " Introduction to Cryptogamic Botany," 

 1857, p. 325. 



f Some of these resemblances were pointed out many years ago by 



Fig. 220 Mature teleu- 

 tospores of f'hragmidiwn 

 buloosttm. Highly magni- 

 fied. After Cooke. 



