Uredospores. 





growths, which become globose and filled with cndochrome 

 (reserve spores) (Plate III, Fig. 14). These abnormal phe- 

 nomena show how nearly allied the different spore-forms 

 of the Uredineae are ; and are especially interesting from 

 an evolutionary point of view. They show that although 

 the uredospore has attained a definite mode of germination 

 proper to itself, yet it has not entirely lost its capability 

 of reverting to, and simulating the mode of growth of 

 other spore-forms.* 



In certain species (Lecythea) are found bodies known 

 as paraphyses, or cystidea. They are in most cases arranged 

 around the circumference of each spore-bed, arching over 

 it and arising from basidia in the same manner as the 

 spores themselves. The paraphyses contain no coloured 

 endochrome. In shape they may be globose, pyriform, 

 subcylindrical, or capitate (Plate III. Figs. 16, 17). 

 Although they cannot be regarded as undeveloped spores, 

 inasmuch as they are pretty much confined to particular 

 species, and do not occur indiscriminately with all, yet 

 from their mode of origin their affinity is clearly with the 

 pseudoperidial cells of the aecidiospores, and to a certain 

 extent they are protective organs in the same way as the 

 latter. From my observations it appears that the presence 

 of paraphyses with certain species greatly depends upon 

 some special condition of the fungus, as they may be 

 absent, or nearly absent, according to special circumstances. 

 I find them constantly present with the uredospores of 

 P.perplexans, when these have arisen not directly, but rather 

 at a considerable distance, from the aecidiospores. On the 

 other hand, when the uredo arises directly from the secidio- 

 spore, they are hardly present at all ; this looks very much 

 as if they were an indication of exhaustion of vital energy 



* Tulasne figures a similar condition in the germination of the uredospores 

 of Cronartium (" 2^ Memoire," tab. xi. ligs. 3, 8, 9). 



D 



