270 



ON THE WHITE RUST OF CABBAGES. 



ever, that he had adopted Schweinitz and Rabenhorst's sectional 

 name of Albugo (Rab., Crypt. Fl., vol. i. p. 13), which is far 

 more expressive ; and as a general principle sectional names 

 ought certainly to be adopted when the sections are raised to 

 the rank of genera. Whether there be more than one species of 

 Cystopus is perhaps doubtful, though the spores differ somewhat 

 in form. Now that the true structure of the genus is ascer- 

 tained, attention may be turned to the question with greater 

 probability of a satisfactory result. 



I observe in conclusion, that Cylindrosporium of Greville 



