536 Mutations 



settes becoming stout and crowded with leaves. 

 Those of 0. rubrinervis on the contrary are 

 thin, of a paler green and with a silvery white 

 surface; the blades are elliptic, often being 

 only 2 cm. or less in width. They are acute 

 at the apex and gradually narrowed into the 

 petiole. 



It is quite evident that such pale narrow 

 leaves must produce smaller quantities of or- 

 ganic food than the darker green and broad 

 organs of the gigas. Perhaps this fact is ac- 

 countable partly, at least, for the more robust 

 growth of the giant in the second year. Per- 

 haps also some relation exists between this dif- 

 ference in chemical activity and the tendency 

 to become annual or biennial. The gigas, as a 

 rule, produces far more, and the rubrinervis 

 far less biennial plants than the Lamarckiana. 

 Annual culture for the one is as unreliable as 

 biennial culture for the other. Rubrinervis 

 may be annual in apparently all specimens, in 

 sunny seasons, which would allow a large part 

 of the gigas to remain in the state of rosettes 

 during the entire first summer. It would be 

 very interesting to obtain a fuller insight into 

 the relation of the length of life to other qual- 

 ities, but yet the facts can only be detailed as 

 they stand. 



Both of these stout species have been found 



