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  INTRODUCTION 
  TO 
  BOTANY 
  

  

  are 
  made 
  up 
  chiefly 
  of 
  stamens, 
  which 
  bear 
  large 
  pollen 
  sacs 
  

   (fig. 
  225) 
  from 
  which 
  pollen 
  is 
  shed 
  in 
  great 
  quantities. 
  It 
  

   may 
  be 
  carried 
  long 
  distances, 
  and 
  its 
  transportation 
  may 
  be 
  

   facilitated 
  by 
  peculiar 
  wings, 
  or 
  outgrowths, 
  upon 
  the 
  walls 
  

   of 
  the 
  pollen 
  grains. 
  Sometimes 
  the 
  pollen 
  is 
  shed 
  in 
  such 
  

   great 
  abundance 
  that 
  some 
  people 
  have 
  thought 
  it 
  was 
  a 
  

   shower 
  of 
  sulphur 
  from 
  some 
  distant 
  volcano. 
  1 
  

  

  275. 
  Pollination. 
  As 
  was 
  learned 
  in 
  the 
  chapter 
  on 
  polli- 
  

   nation 
  and 
  fertilization, 
  the 
  pollen 
  (or 
  microspores) 
  must 
  be 
  

   placed 
  on 
  the 
  part 
  of 
  the 
  flower 
  which 
  bears 
  the 
  ovules 
  before 
  

   the 
  pollen 
  grows. 
  It 
  was 
  also 
  learned 
  that 
  the 
  proper 
  placing 
  

   of 
  the 
  pollen 
  is 
  known 
  as 
  pollination, 
  and 
  considerable 
  study 
  

   was 
  made 
  of 
  the 
  different 
  ways 
  in 
  which 
  pollination 
  occurs. 
  

   In 
  the 
  pines 
  the 
  } 
  r 
  oung 
  seed 
  cones 
  stand 
  upright 
  and 
  open 
  

   (fig. 
  220) 
  at 
  the 
  time 
  the 
  pollen 
  is 
  being 
  shed. 
  If 
  pollen 
  grains 
  

   chance 
  to 
  come 
  into 
  the 
  seed 
  cones, 
  they 
  slide 
  down 
  upon 
  the 
  

   leaf-like 
  parts 
  to 
  the 
  base, 
  where 
  the 
  sporangia 
  are 
  borne. 
  By 
  

   means 
  of 
  a 
  sticky 
  secretion 
  they 
  are 
  then 
  caused 
  to 
  adhere 
  to 
  

   the 
  tip 
  of 
  the 
  ovule, 
  and 
  pollination 
  is 
  completed. 
  In 
  order 
  

   that 
  pollination 
  in 
  pines 
  may 
  be 
  complete, 
  it 
  is 
  evident 
  that 
  

   the 
  air 
  must 
  be 
  full 
  of 
  pollen 
  when 
  the 
  ovules 
  are 
  ready 
  to 
  

   receive 
  it 
  ; 
  and 
  this 
  is 
  the 
  case. 
  The 
  pollen 
  is 
  not 
  only 
  very 
  

   abundant 
  but, 
  because 
  of 
  its 
  lightness, 
  is 
  easily 
  transported. 
  

  

  276. 
  Fertilization. 
  In 
  the 
  ferns 
  the 
  egg 
  is 
  borne 
  in 
  the 
  

   archegonium, 
  the 
  neck 
  of 
  which 
  opens 
  to 
  the 
  exterior, 
  so 
  that 
  

   the 
  sperm" 
  may 
  swim 
  directly 
  into 
  the 
  passageway 
  leading 
  

   to 
  the 
  egg. 
  In 
  the 
  gymnosperms, 
  on 
  the 
  contrary, 
  the 
  egg 
  is 
  

   imbedded 
  within 
  the 
  tissue 
  of 
  the 
  ovule. 
  After 
  the 
  pollen 
  

   grain 
  falls 
  upon 
  the 
  ovule, 
  there 
  grows 
  from 
  its 
  wall 
  a 
  tube 
  

  

  1 
  Unfortunately 
  for 
  flic 
  learner, 
  each 
  of 
  the 
  structures 
  that 
  compose 
  the 
  

   staininatf 
  cone 
  has 
  had 
  t\\o 
  or 
  more 
  names 
  applied 
  to 
  it, 
  all 
  of 
  which 
  are 
  in 
  

   use 
  in 
  botanical 
  writings. 
  The 
  pollen 
  Drains 
  are 
  also 
  known 
  as 
  iiii<T*i>nrr.\ 
  

   (small 
  .-pure*) 
  ; 
  the 
  pollen 
  sacs 
  are 
  called 
  microsporangia 
  (small 
  spore 
  sac.-) 
  ; 
  

   the 
  stamens 
  are 
  called 
  mfcroapOTOphytts 
  (Bm&ll 
  BQOTQ 
  leaves); 
  the 
  whole 
  stam- 
  

   ina! 
  e 
  llower 
  is 
  called 
  the 
  xl 
  i'l>ihix. 
  a 
  name 
  which 
  was 
  used 
  for 
  the 
  cone 
  of 
  

   the 
  club 
  moss 
  and 
  in 
  a 
  way 
  distinguishes 
  it 
  from 
  the 
  type 
  of 
  flower 
  that 
  is 
  

   found 
  in 
  the 
  angiosperms. 
  

  

  