The Genus Ravenelia. By M. C. Cooke. 389 



exceed their diameter in length ; this is the case with Ft,. Eohsoni 

 which in some respects is very similar to B. aculeifera. 



The barren cysts which surround the capitules in some species 

 yet require to be investigated. All that we have yet succeeded in 

 determining is that these cysts readily separate individually in 

 B. Indiea, that after prolonged saturation they become inflated and 

 subglobose, but the cell membrane is thin and delicate, and in no 

 instance have we seen them with any granular or protoplasmic 

 contents. As already observed, these are points which cannot be 

 cleared up at once, in the absence of living or fresh specimens. 



As to the stem, in both B. Indiea and B. fflandulfeformis, it is 

 quite certain that, under pressure, it separates into parallel tubes, 

 as in the stem of Stilbum and some other moulds with a com- 

 pound stem. Probably, but this is only a speculation, the number 

 of threads may equal that of the pseudospores in the capitule. 



Finally, as to germination. The very cold weather and very 

 old specimens are not at all favourable for experiments in germina- 

 tion, and hence the utmost that we have been able to accomplish 

 has been to obtain single short germinating threads from the apices 

 of a few of the pseudospores in B. aculeifera which were the pro- 

 duction of last year (Fig. 14). B. glandulxformis of three to 

 five years old refused to germinate at all, and until we can obtain 

 more recent specimens, at least not more than twelve months old, 

 we cannot hope to carry on the germination of the pseudospores so 

 far as the production of the secondary spores, if such bodies are 

 really produced on the germinating threads, as in Puccinia and 

 Phragmidium, 



