﻿74 
  

  

  INTRODUCTION 
  TO 
  BOTANY 
  

  

  narrow 
  at 
  the 
  base 
  and 
  wider 
  at 
  the 
  tip, 
  as 
  in 
  the 
  evening 
  prim- 
  

   rose, 
  so 
  that 
  nearly 
  all 
  the 
  space 
  between 
  the 
  leaves 
  is 
  tilled 
  in. 
  

   During 
  which 
  year 
  of 
  the 
  life 
  of 
  a 
  biennial 
  is 
  its 
  principal 
  

   work 
  photosynthetic 
  ? 
  During 
  which 
  year 
  is 
  it 
  reproductive? 
  

  

  Why 
  are 
  beets, 
  carrots, 
  parsnips, 
  

   and 
  salsify 
  used 
  as 
  food 
  at 
  the 
  

   end 
  of 
  the 
  tirst 
  season's 
  growth 
  ? 
  

  

  72. 
  Leaf 
  mosaics. 
  Any 
  combi- 
  

   nation 
  of 
  leaves 
  (whether 
  found 
  

   in 
  rosette 
  plants 
  or 
  on 
  longer 
  

   stems) 
  in 
  which 
  the 
  space 
  is 
  very 
  

   fully 
  occupied, 
  with 
  few 
  spaces 
  

   between 
  the 
  leaves, 
  is 
  called 
  a 
  

   leaf 
  mosaic. 
  Walls 
  covered 
  with 
  

   Japanese 
  ivy 
  furnish 
  beautiful 
  

   examples 
  of 
  leaf 
  mosaics 
  on 
  a 
  

   large 
  scale, 
  and 
  many 
  of 
  OUT 
  

   common 
  house 
  plants 
  illustrate 
  

   the 
  same 
  phenomenon. 
  In 
  any 
  

   leaf 
  mosaic 
  many 
  of 
  the 
  leaves 
  

   occupy 
  a 
  very 
  different 
  posi- 
  

   tion 
  from 
  that 
  which 
  they 
  would 
  

   have 
  taken 
  if 
  borne 
  on 
  a 
  vertical 
  

   stem. 
  

  

  73. 
  Climbing 
  into 
  the 
  light. 
  

  

  Tins 
  vino 
  is 
  elimbiug 
  on 
  an 
  American 
  ]\[ 
  ilnv 
  plants, 
  of 
  vei'V 
  diverse 
  

   elm. 
  The 
  height 
  up 
  to 
  the 
  branch 
  / 
  .*. 
  

  

  is 
  about 
  60 
  feet, 
  and 
  the 
  average 
  cir- 
  families, 
  secure 
  a 
  better 
  expo- 
  

   sure 
  of 
  the 
  leaves 
  to 
  light 
  by 
  

   climbing. 
  The 
  principal 
  types 
  

   of 
  climbing 
  plants 
  are 
  four 
  in 
  

   number: 
  xminilhrs, 
  like 
  the 
  common 
  climbing 
  roses; 
  root 
  

   climbers, 
  like 
  the 
  poison 
  ivy 
  (fig. 
  56) 
  and 
  the 
  English 
  ivy 
  

   (fig. 
  40); 
  twiners, 
  like 
  the 
  morning-glory; 
  and 
  temlril 
  c/i//tl>ers, 
  

   like 
  the 
  grapevine. 
  The 
  only 
  way 
  in 
  which 
  one 
  can 
  get 
  a 
  

   thorough 
  knowledge 
  of 
  the 
  behavior 
  of 
  climbers 
  is 
  to 
  watch 
  

   them 
  throughout 
  as 
  much 
  as 
  possible 
  of 
  the 
  growing 
  season. 
  

  

  FIG. 
  57. 
  The 
  wild 
  frost 
  grape, 
  a 
  

   typical 
  tendril 
  climber 
  

  

  eiinilVreiiee 
  of 
  the 
  main 
  vine, 
  3 
  feet. 
  

   Redrawn 
  and 
  simplified 
  from 
  a 
  pho- 
  

   tograph 
  by 
  Robert 
  Ridi^way 
  

  

  