1 8 British UredinccB and UstilaginecE. 



although I repeatedly examined it for them. These two 

 cases, the Sempervivum and the Tragopogon, in both of 

 which perfectly normal, and in the latter instance function- 

 ally active, secidiospores were produced without the presence 

 of spermogonia, show, at any rate, that each individual 

 aecidial cup was not the result of a spermatial fecundation. 

 It may have been that in both instances the plant bore 

 spermogonia before they came under observation, and 

 that they both bore within them an already fecundated 

 mycelium ; but this is only a supposition, and, even if it 

 be admitted as possible, yet it does away entirely with 

 the analogy of the sexually produced spore-beds of the 

 lichen-fungi and Polystigma, in which each spore-bed is 

 the result of a separate spermatial impregnation of the 

 trichogyne. Nor is the case of the Uredineae with short- 

 lived mycelia more tenable. If with them each secidial 

 cup is a sexual product, then it cannot arise in the first 

 instance without a spermatial fecundation. But Schroter * 

 has shown that when he produced the ?ecidium of P. porri 

 (Sow.) by infecting the Allium schcenoprasiim with the 

 teleutospores, the resulting aecidia were always unaccom- 

 panied by spermogonia, as was also the case when they 

 occurred on onion {A. cepa) ; and, further, he found while 

 the vernal specimens of the secidiospores of Uromyces ervi 

 on Erviim hirstitum and of Puccinia galii on G. aparine 

 were accompanied by spermogonia, yet those produced 

 later in the year were invariably without this accompani- 

 ment. If the spermatia were necessary to the development 

 of the aecidia in spring, how could they be dispensed with 

 by the same formation in autumn ? The fact, however, 

 stands that spermogonia almost always accompany secidio- 

 spores ; but not only is this the case with the true ^cidia, 

 but also with the analogous Caeomata — analogous in as 



* Schroter, " Cohn's Beitrage," vol. ii. p. 83. 



