﻿12 
  

  

  INTRODUCTION 
  TO 
  BOTAXY 
  

  

  stem 
  will 
  be 
  discussed 
  in 
  later 
  chapters. 
  P>y 
  means 
  of 
  their 
  

   upright 
  position, 
  stems 
  may 
  support 
  the 
  branches 
  and 
  leaves 
  

   in 
  such 
  a 
  way 
  that 
  they 
  are 
  upheld 
  in 
  the 
  air. 
  Support 
  IB 
  evi- 
  

   dently 
  one 
  of 
  the 
  conspicuous 
  functions 
  served 
  by 
  plant 
  stems. 
  

   Many 
  plants 
  live 
  for 
  only 
  one 
  year 
  ( 
  .IHI/IKI/* 
  ) 
  or 
  two 
  years 
  

   ( 
  1,1,'iniiiilx) 
  ; 
  ill 
  such 
  plants 
  large 
  and 
  strong 
  stems 
  are 
  not 
  

   often 
  found. 
  ( 
  Mher 
  kinds 
  of 
  plants 
  may 
  live 
  for 
  two 
  or 
  more 
  

   years 
  ( 
  //, 
  /<////////*). 
  \Yoody 
  perennials 
  may 
  live 
  for 
  hundreds 
  

  

  of 
  years, 
  and 
  their 
  stems 
  usually 
  

   increase 
  in 
  thickness 
  from 
  year 
  

   to 
  year, 
  until, 
  in 
  the 
  case 
  of 
  trees, 
  

   stems 
  are 
  sometimes 
  developed 
  

   which 
  are 
  several 
  feet 
  in 
  thick- 
  

   ness, 
  much 
  over 
  a 
  hundred 
  feet 
  

   in 
  height, 
  and 
  of 
  such 
  strength 
  

   that 
  very 
  heavy 
  tops 
  are 
  upheld 
  

   throughout 
  the 
  severest 
  storms. 
  

   The 
  increase 
  in 
  thickness 
  is 
  shown 
  

   by 
  1 
  he 
  <iiiinil 
  rhujx 
  of 
  wood 
  ( 
  tig. 
  X). 
  

   Often 
  the 
  an 
  - 
  e 
  of 
  a 
  woody 
  stem 
  

  

  O 
  / 
  

  

  may 
  be 
  indicated 
  approximately 
  

   by 
  its 
  annual 
  rings, 
  but 
  that 
  these 
  

   are 
  not 
  always 
  truly 
  annual 
  rings 
  

   is 
  shown 
  by 
  the 
  fact 
  that 
  when 
  

   there 
  are 
  intermittent 
  favorable 
  

   unfavorable 
  growing 
  periods 
  within 
  the 
  same 
  season, 
  

  

  

  fell*'' 
  

   **? 
  

  

  Fi... 
  X. 
  ( 
  )iic 
  ipuirtrr 
  of 
  a 
  cross 
  

   nt' 
  a 
  slick 
  nf 
  i>ak 
  \\i\ 
  

  

  in. 
  medullary 
  rays. 
  running 
  1'nnii 
  

   hark 
  tn 
  ]>illi: 
  r, 
  annual 
  rinus: 
  l>, 
  

   honndarirs 
  between 
  rinjis, 
  inn-mis 
  

  

  ('rum 
  presence 
  of 
  many 
  ducts 
  ; 
  /'. 
  in- 
  

  

  trrior 
  tilirous 
  layers 
  of 
  dead 
  liark 
  ; 
  

   /./. 
  hard 
  ]ilal<-s 
  n!' 
  di-ad 
  liark. 
  s|>lil- 
  

   tinu 
  r 
  a\\a> 
  I'l-mii 
  i-arh 
  other 
  hut 
  at- 
  

   larln-il 
  t,i 
  hark 
  lirncath. 
  Knlucnl 
  

  

  more 
  than 
  one 
  ring 
  may 
  be 
  formed 
  within 
  one 
  year. 
  Cases 
  

   are 
  known 
  of 
  young 
  trees 
  that 
  have 
  almost 
  twice 
  as 
  many 
  

  

  v 
  C? 
  J 
  

  

  ring's 
  as 
  the 
  number 
  of 
  years 
  of 
  their 
  aiiv. 
  

  

  / 
  O 
  

  

  10. 
  Stems 
  as 
  passageways 
  for 
  liquids. 
  When 
  the 
  stem 
  of 
  

   an 
  acti\cl\ 
  growing 
  plant 
  is 
  cut, 
  water 
  sometimes 
  exudes 
  

   upon 
  the 
  cut 
  surface 
  of 
  the 
  stump. 
  The 
  same 
  outpouring 
  of 
  

   water 
  is 
  seen 
  when 
  a 
  leaf 
  of 
  a 
  corn 
  plant 
  is 
  peeled 
  away 
  from 
  

   the 
  stalk. 
  \Vhen 
  we 
  wish 
  to 
  keep 
  cut 
  (lowers 
  in 
  a 
  fresh 
  con- 
  

   dition, 
  we 
  place 
  their 
  stems 
  iii 
  water. 
  If 
  we 
  should 
  place 
  a 
  

   fresh 
  leaf 
  of 
  celery 
  in 
  a 
  solution 
  of 
  one 
  of 
  the 
  aniline 
  dyes 
  

  

  