﻿ROOTS 
  AND 
  THEIR 
  RELATION 
  TO 
  PLANTS 
  33 
  

  

  5. 
  What 
  kinds 
  of 
  plants 
  would 
  be 
  useful 
  in 
  preventing 
  the 
  drifting 
  

   of 
  sand 
  in 
  dunes 
  like 
  those 
  of 
  figure 
  1 
  ? 
  

  

  6. 
  What 
  are 
  some 
  reasons 
  why 
  embankments, 
  as 
  of 
  reservoirs 
  and 
  

   railroad 
  rights 
  of 
  way, 
  should 
  be 
  kept 
  well 
  grassed 
  over 
  ? 
  

  

  7. 
  Just 
  where 
  would 
  you 
  place 
  soil 
  fertilizers 
  for 
  prompt 
  effect 
  on 
  

   old 
  apple 
  or 
  pear 
  trees 
  ? 
  

  

  8. 
  Make 
  a 
  list 
  of 
  all 
  the 
  plants 
  that 
  you 
  can 
  find 
  producing 
  aerial 
  

   roots, 
  and 
  try 
  to 
  explain 
  their 
  use 
  in 
  each 
  case. 
  

  

  9. 
  What 
  common 
  plants 
  are 
  almost 
  always 
  propagated 
  by 
  roots 
  ? 
  

   What 
  ones 
  are 
  propagated 
  sometimes 
  in 
  this 
  way 
  and 
  sometimes 
  in 
  

   other 
  ways 
  ? 
  

  

  10. 
  When 
  roots 
  are 
  uncovered 
  by 
  the 
  washing 
  away 
  of 
  the 
  soil, 
  do 
  

   they 
  develop 
  bark 
  like 
  that 
  of 
  the 
  stem 
  ? 
  

  

  