﻿68 
  

  

  INT 
  in 
  (DICTION 
  TO 
  BOTANY 
  

  

  As 
  the 
  brand 
  i 
  lengthens, 
  it 
  somewhat 
  displaces 
  the 
  annual 
  

   layers 
  of 
  the 
  stem 
  from 
  which 
  it 
  grows, 
  and 
  the 
  branch 
  forms 
  

   its 
  own 
  animal 
  rings. 
  Knots 
  arc 
  not 
  all 
  due 
  to 
  the 
  growth 
  

   of 
  brandies, 
  but 
  most 
  of 
  them 
  are, 
  as 
  may 
  be 
  seen 
  from 
  

   figure 
  40. 
  If 
  a 
  knot-forming 
  branch 
  dies 
  early, 
  new 
  wood 
  

   forms 
  over 
  it 
  and 
  covers 
  it 
  np, 
  as 
  the 
  lignre 
  shows; 
  but 
  if 
  it 
  

   continues 
  to 
  live 
  as 
  long 
  as 
  the- 
  main 
  stem 
  does, 
  it 
  gives 
  rise 
  

  

  to 
  a 
  knot 
  that 
  reaches 
  to 
  the 
  outer- 
  

  

  H 
  

  

  most 
  layer 
  of 
  wood 
  in 
  the 
  stem. 
  

  

  In 
  figure 
  40 
  which 
  knot, 
  a 
  or 
  b, 
  

   would 
  be 
  the 
  more 
  likely 
  to 
  in- 
  

   jure 
  the 
  timber? 
  

  

  66. 
  Internal 
  structure 
  of 
  the 
  mon- 
  

   ocotyledonous 
  stem. 
  In 
  the 
  very 
  

   young 
  monocotyledonons 
  stems 
  of 
  

   seedlings 
  thefibrovasenlar 
  bundles 
  

   are 
  constructed 
  like 
  those 
  of 
  di- 
  

   cotyledons. 
  The 
  wood 
  elements 
  

   are 
  on 
  the 
  one 
  side 
  and 
  the 
  corti- 
  

   cal 
  elements 
  on 
  the 
  other. 
  In 
  the 
  

   full-orown 
  stems 
  of 
  most 
  mono- 
  

  

  O 
  

  

  cotyledons 
  the 
  bundles 
  have 
  their 
  

   vessels 
  and 
  other 
  wood 
  elements 
  arranged 
  in 
  a 
  hollow 
  cylinder 
  

   inclosing 
  that 
  part 
  of 
  the 
  bundle 
  which 
  corresponds 
  to 
  the 
  por- 
  

   tion 
  shown 
  outside 
  of 
  the 
  cambium 
  ring 
  in 
  tignre 
  4i>, 
  A. 
  In 
  

   the 
  adult 
  monocotyledonons 
  stem 
  (when 
  it 
  is 
  solid) 
  the 
  bun- 
  

   dles 
  occur 
  scattered 
  all 
  through 
  the 
  pith, 
  as 
  shown 
  in 
  a 
  section 
  

   of 
  asparagus 
  or 
  corn 
  stem 
  (fig. 
  47). 
  No 
  such 
  complicated 
  bark 
  

   as 
  that 
  of 
  woody 
  dicotyledons 
  is 
  found 
  in 
  monocotyledons. 
  

  

  67. 
  Growth 
  in 
  thickness 
  of 
  the 
  monocotyledonous 
  stem. 
  The 
  

   very 
  young 
  stems 
  of 
  monocotyledons 
  may 
  for 
  a 
  time 
  increase 
  

   considerably 
  in 
  diameter 
  by 
  the 
  formation 
  of 
  new 
  bundles 
  

   within 
  them. 
  But 
  in 
  monocotyledons 
  all 
  the 
  cambium 
  becomes 
  

   changed 
  into 
  other 
  tissues, 
  so 
  that 
  none 
  is 
  left, 
  as 
  it 
  is 
  in 
  

   dicotyledons, 
  to 
  develop 
  new 
  tissue. 
  In 
  monocotyledons 
  the 
  

   bundles 
  are 
  said 
  to 
  be 
  closed^ 
  while 
  those 
  of 
  dicotyledons, 
  in 
  

  

  FIG. 
  47. 
  One 
  quarter 
  of 
  a 
  cross 
  

   section 
  of 
  a 
  corn 
  stem, 
  showing 
  

   the 
  hunt 
  cortex 
  and 
  within 
  it 
  

   the 
  soft 
  pith, 
  throughout 
  which 
  

   many 
  tibrovascular 
  bundles 
  are 
  

   irregularly 
  scattered 
  

  

  