﻿272 
  

  

  INTRODUCTION 
  TO 
  BOTANY 
  

  

  and 
  no 
  such 
  description 
  is 
  here 
  attempted. 
  In 
  all 
  leaves 
  the 
  

   fibrovascular 
  bundles 
  extend 
  throughout 
  the 
  leafstalk 
  into 
  

   the 
  leaves, 
  where 
  they 
  are 
  known 
  as 
  the 
  veins 
  of 
  the 
  leaf. 
  

  

  FIG. 
  209. 
  The 
  rootstock 
  of 
  a 
  fern 
  

  

  The 
  outer 
  part 
  of 
  the 
  stem 
  is 
  made 
  up 
  of 
  hard 
  tissue, 
  and 
  in 
  the 
  interior 
  are 
  also 
  

  

  bundles 
  of 
  hard 
  tissue 
  (s) 
  known 
  assdcrenchyma; 
  numerous 
  woody 
  bundles 
  (f.b) 
  

  

  are 
  also 
  surrounded 
  by 
  the 
  large 
  amount 
  of 
  pith 
  

  

  FIG. 
  210. 
  Diagram 
  of 
  cross 
  section 
  of 
  a 
  fern 
  leaf 
  

  

  On 
  the 
  underside 
  of 
  the 
  leaf 
  are 
  the 
  indusium 
  (?) 
  and 
  the 
  sporangia 
  (s) 
  ; 
  within 
  

   the 
  sporangia 
  are 
  the 
  spores. 
  After 
  Engler 
  and 
  Prantl 
  

  

  