﻿INTRODUCTION 
  TO 
  BOTANY 
  

  

  6. 
  Poisonous 
  or 
  intoxicating 
  plants 
  injure 
  horses, 
  cattle, 
  and 
  

   sheep. 
  

  

  7. 
  Some 
  spiny 
  plants 
  (such 
  as 
  the 
  smaller 
  cacti) 
  and 
  burs 
  

   (like 
  the 
  sand 
  bur) 
  may 
  lame 
  the 
  feet 
  of 
  domestic 
  animals. 
  

  

  Thorny 
  shrubs 
  are 
  very 
  

   troublesome 
  to 
  woolgrow- 
  

   ers, 
  as 
  they 
  pull 
  out 
  much 
  

   wool, 
  and 
  the 
  burs 
  greatly 
  

   injure 
  the 
  quality 
  of 
  the 
  

   fleece. 
  

  

  8. 
  Certain 
  weeds, 
  when 
  

   eaten 
  by 
  cows, 
  render 
  milk 
  

   unpalatable 
  or 
  ill-scented. 
  

  

  9. 
  Weed 
  seeds 
  injure 
  the 
  

   quality 
  and 
  affect 
  the 
  price 
  

   of 
  clover 
  and 
  other 
  seeds 
  

   that 
  are 
  raised 
  for 
  sale. 
  

  

  313. 
  Amount 
  of 
  damage 
  

   caused 
  by 
  weeds. 
  It 
  is 
  im- 
  

   possible 
  to 
  put 
  into 
  exact 
  

   figures 
  the 
  amount 
  of 
  dam- 
  

   age 
  annually 
  done 
  by 
  weeds 
  

   in 
  the 
  Tinted 
  States, 
  but 
  

   it 
  probably 
  aggregates 
  over 
  

   $200,000,000 
  a 
  year. 
  1 
  

  

  The 
  expense 
  caused 
  by 
  

   weeds 
  is 
  largely 
  for 
  extra 
  

   labor 
  of 
  men 
  and 
  animals, 
  

  

  

  FIG. 
  243. 
  

  

  (1,1,1.1, 
  T. 
  

  

  red 
  clover 
  

  

  parasitic 
  mi 
  

  

  .1, 
  habit 
  sketch 
  of 
  part 
  of 
  the 
  parasite 
  and 
  

  

  tin- 
  host 
  : 
  A', 
  iiiirtiuii 
  nl' 
  stem 
  (if 
  tin- 
  dodder, 
  

   showing 
  protuberances 
  from 
  which 
  haiis- 
  

   tnria 
  ]i:iss 
  into 
  the 
  stem 
  of 
  tin- 
  host 
  : 
  C, 
  

   a 
  single 
  tlower 
  of 
  the 
  dodder. 
  l> 
  :md 
  '' 
  

   coiisidcralily 
  ina-nilicd. 
  Modified 
  after 
  

   " 
  Flora 
  Danica 
  " 
  

  

  1 
  The 
  estimate 
  hero 
  iriveii 
  is 
  liy 
  

   Professor 
  Freileriek 
  V. 
  Coville, 
  

   and 
  is 
  based 
  on 
  the 
  assumption 
  

   that 
  the 
  loss 
  may 
  amount 
  to 
  5 
  

   per 
  cent 
  of 
  the 
  total 
  value 
  of 
  the 
  

  

  principal 
  crops 
  of 
  the 
  United 
  States. 
  The 
  estimated 
  value 
  of 
  the 
  crop 
  of 
  

   corn, 
  \\heat, 
  oats, 
  barley, 
  rye, 
  buckwheat, 
  tlaxseed. 
  rice, 
  potatoes, 
  hay, 
  

   tobacco, 
  and 
  cotton 
  for 
  the 
  year 
  I!tl2 
  was 
  $4,603,000,000. 
  

  

  Another 
  estimate 
  by 
  an 
  expert 
  in 
  the 
  Department 
  of 
  Agriculture 
  places 
  

   the 
  loss 
  at 
  about 
  $300,000,000. 
  

  

  