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 riihrinervis 

 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, but gigas will ordinarily 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 qualities, but 

 as yet the facts can only be detailed as 

 they stand. 



Both of these stout species have been found 



