﻿CHAPTER 
  V 
  

  

  THE 
  STEM 
  AND 
  THE 
  LEAF 
  

  

  Fi<;. 
  37. 
  Beef 
  wood, 
  C<i*iHii-hi. 
  an 
  Austra- 
  

   lian 
  switch 
  plant 
  destitute 
  of 
  foliage 
  leaves 
  

   and 
  depending 
  on 
  the 
  chlorophyll-containing 
  

   cells 
  of 
  the 
  bark 
  for 
  photosynthesis 
  

  

  Photograph 
  by 
  Robert 
  Cameron 
  

  

  55. 
  Work 
  of 
  the 
  leafy 
  

   shoot. 
  How 
  plant 
  food 
  

   is 
  made 
  from 
  raw 
  mate- 
  

   rials 
  has 
  been 
  briefly 
  ex- 
  

   plained 
  in 
  Chapter 
  IV. 
  

   In 
  almost 
  all 
  of 
  the 
  

   higher 
  plants 
  this 
  food 
  

   making 
  is 
  carried 
  on 
  

   by 
  the 
  cooperation 
  of 
  

   the 
  stem 
  and 
  the 
  leaf. 
  

   Taken 
  together, 
  they 
  

   are 
  known 
  as 
  the 
  shoot, 
  

   so 
  that 
  the 
  parts 
  of 
  a 
  

   flowering 
  plant 
  (before 
  

   it 
  begins 
  to 
  flower) 
  are 
  

   root 
  and 
  shoot. 
  

  

  56. 
  Photosynthesis 
  in 
  

   the 
  stem. 
  Among 
  seed 
  

   plants 
  in 
  general 
  it 
  is 
  

   the 
  leaves 
  that 
  do 
  by 
  

   far 
  the 
  greater 
  part 
  of 
  

   the 
  work 
  of 
  photosyn- 
  

   thesis, 
  but 
  some 
  plants, 
  

   as 
  the 
  cacti 
  (fig. 
  66), 
  

   are 
  practically 
  leafless 
  1 
  

  

  i 
  That 
  is, 
  they 
  have 
  no 
  

   leaves 
  which 
  can 
  do 
  any 
  

   food-making 
  or 
  which 
  at 
  all 
  

   resemble 
  ordinary 
  leaves. 
  

  

  