﻿SEED 
  DISTRIBUTION 
  

  

  169 
  

  

  Evidently 
  no 
  kind 
  of 
  flowering 
  plant 
  actually 
  increases 
  at 
  

   any 
  such 
  rate 
  as 
  has 
  just 
  been 
  suggested, 
  or 
  it 
  would 
  soon 
  

   crowd 
  most 
  others 
  out 
  of 
  existence. 
  The 
  means 
  by 
  which 
  the 
  

   unlimited 
  multiplication 
  of 
  any 
  one 
  

   species 
  is 
  prevented 
  are 
  lack 
  of 
  ex- 
  

   tremely 
  rapid 
  and 
  thorough 
  means 
  of 
  

   disseminating 
  the 
  seeds, 
  multiplication 
  

   of 
  the 
  insect 
  and 
  plant 
  enemies 
  of 
  the 
  

   species 
  (a 
  factor 
  which 
  is 
  often 
  not 
  

   very 
  important), 
  and 
  over-crowding 
  or 
  

   competition 
  with 
  other 
  plants 
  of 
  the 
  

   same 
  or 
  of 
  different 
  species. 
  

  

  161. 
  Competition 
  as 
  a 
  check 
  on 
  in- 
  

   crease. 
  No 
  one 
  can 
  realize 
  just 
  what 
  

   competition 
  among 
  plants 
  means 
  un- 
  

   less 
  he 
  makes 
  some 
  careful 
  out-of-door 
  

   studies 
  of 
  plants 
  growing 
  under 
  condi- 
  

   tions 
  of 
  great 
  overcrowding. 
  A 
  por- 
  

   tion 
  of 
  a 
  grainfield 
  too 
  thickly 
  sown, 
  

   a 
  very 
  weedy 
  bit 
  of 
  garden 
  soil 
  left 
  

   to 
  itself 
  for 
  the 
  whole 
  growing 
  season, 
  

   or 
  a 
  piece 
  of 
  recently 
  cleared 
  forest 
  

   in 
  which 
  coppice 
  growth 
  is 
  starting 
  

   from 
  old 
  stumps, 
  or 
  where 
  seedling 
  

   trees 
  are 
  springing 
  up 
  in 
  great 
  num- 
  

   bers 
  --any 
  one 
  of 
  these 
  will 
  teach 
  a 
  

   most 
  important 
  lesson. 
  The 
  writer 
  

   has 
  found 
  wild-black-cherry 
  seedlings, 
  

   to 
  the 
  number 
  of 
  more 
  than 
  100 
  to 
  

   the 
  square 
  foot, 
  beginning 
  to 
  grow 
  in 
  

   the 
  spring 
  under 
  a 
  large 
  wild-cherry 
  

   tree. 
  As 
  the 
  parent 
  tree 
  was 
  in 
  thrifty 
  

  

  condition 
  and 
  its 
  top 
  was 
  nearly 
  30 
  feet 
  in 
  diameter, 
  there 
  

   might 
  have 
  been 
  some 
  70,000 
  seedling 
  cherries 
  every 
  year 
  

   killed 
  by 
  crowding 
  and 
  shade 
  under 
  this 
  one 
  tree, 
  although, 
  

   in 
  fact, 
  there 
  were 
  never 
  so 
  many 
  as 
  this. 
  

  

  FIG. 
  150. 
  Cockleburs 
  

  

  This 
  troublesome 
  weed 
  often 
  

   grows 
  along 
  a 
  path, 
  where 
  

   men 
  carry 
  the 
  seeds 
  back 
  and 
  

   forth 
  in 
  their 
  clothing, 
  and 
  

   animals 
  in 
  their 
  hair 
  or 
  fur 
  

  

  