﻿270 
  

  

  INTRODUCTION 
  TO 
  BOTAXY 
  

  

  of 
  these 
  ancient 
  plants 
  doubtless 
  represented 
  classes 
  that 
  are 
  

   extinct, 
  and 
  others 
  were 
  the 
  older 
  members 
  or 
  the 
  ancestors 
  

   of 
  the 
  classes 
  which 
  we 
  no\v 
  have, 
  which 
  in 
  some 
  cases 
  are 
  

   represented 
  by 
  only 
  a 
  few 
  kinds 
  of 
  living 
  plants. 
  

  

  Most 
  ferns 
  grow 
  in 
  moist 
  regions, 
  but 
  some 
  species 
  are 
  found 
  

   in 
  peculiar! 
  v 
  dry 
  situations, 
  even 
  growing 
  like 
  lichens 
  on 
  nearly 
  

  

  --- 
  - 
  " 
  . 
  

  

  . 
  "V 
  

  

  * 
  ~ 
  ,r* 
  .- 
  ^r-^' 
  

  

  " 
  

  

  FMJ. 
  207. 
  A 
  group 
  of 
  inaidenhair 
  IVrns 
  

   Photograph 
  by 
  W. 
  H. 
  P. 
  Huber 
  

  

  bare 
  rocks. 
  Although 
  they 
  show 
  considerable 
  variation 
  in 
  

   I'oi'iu, 
  they 
  can 
  in 
  nearly 
  all 
  cases 
  be 
  distinguished 
  from 
  other 
  

   plants 
  by 
  their 
  greatly 
  divided, 
  feather-like 
  leaves 
  (fig. 
  207). 
  

   Ferns 
  have 
  great 
  range 
  in 
  si/.e, 
  from 
  very 
  small, 
  lowly 
  plants 
  

   to 
  those 
  as 
  high 
  as 
  a 
  man's 
  head, 
  and 
  to 
  the 
  tropical 
  tree 
  ferns 
  

   that 
  may 
  be 
  forty 
  feet 
  or 
  more 
  in 
  height. 
  They 
  may 
  occur 
  

   singly 
  oi 
  1 
  in 
  thickets 
  so 
  dense 
  as 
  to 
  make 
  it 
  dillieult 
  to 
  penetrate 
  

   them. 
  In 
  all 
  except 
  the 
  tree 
  ferns 
  the 
  parts 
  of 
  the 
  plant 
  that 
  

   we 
  see 
  are 
  the 
  leaves 
  ; 
  the 
  stems 
  and 
  the 
  roots 
  are 
  underground. 
  

  

  