﻿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, 
  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 
  

  

  