﻿144 
  

  

  INTKODUCTION 
  TO 
  BOTANY 
  

  

  FIG. 
  127. 
  Structure 
  of 
  an 
  ear 
  of 
  corn 
  (pistil- 
  

   late 
  flower 
  cluster) 
  

  

  A, 
  section 
  of 
  yoiin^ 
  car 
  In-fore 
  fertilization 
  of 
  the 
  

   ovules 
  (grains) 
  ; 
  i/r, 
  axis 
  of 
  spike 
  (cob) 
  ; 
  si. 
  ends 
  

   of 
  silk 
  (styles 
  and 
  stigmas'); 
  /', 
  maunilied 
  B6C- 
  

   tion 
  through 
  a 
  urain. 
  showing 
  bracts 
  around 
  the 
  

  

  ovnry. 
  tl 
  vule 
  (), 
  ami 
  the 
  base 
  of 
  the 
  style; 
  

  

  C, 
  upper 
  portion 
  of 
  style, 
  \\ith 
  the 
  stigmas 
  (at) 
  

   considerahly 
  uiagiiiiied. 
  After 
  F. 
  L. 
  Sargent 
  

  

  137. 
  The 
  potato 
  and 
  

   the 
  grape 
  ; 
  flowers 
  open 
  

   to 
  all 
  insect 
  visitors. 
  

   The 
  potato 
  is 
  a 
  famil- 
  

   iar 
  example 
  of 
  a 
  flown- 
  

   with 
  wide-<>pen 
  corolla 
  

   (fig. 
  128), 
  easily 
  entered 
  

   by 
  any 
  kind 
  of 
  insect. 
  

   The 
  flowers, 
  with 
  their 
  

   white 
  corollas 
  and 
  con- 
  

   ical 
  group 
  of 
  yellow 
  

   anthers, 
  are 
  moderately 
  

   conspicuous 
  and 
  are 
  vis- 
  

   ited 
  by 
  insects 
  for 
  the 
  

   sake 
  of 
  the 
  pollen 
  which 
  

   they 
  afford. 
  They 
  yield 
  

   no 
  nectar. 
  

  

  The 
  flowers 
  of 
  the 
  

   grape 
  are 
  small 
  and 
  

   greenish. 
  The 
  corolla 
  

   does 
  not 
  expand 
  but 
  

   falls 
  off 
  in 
  one 
  piece 
  as 
  

   soon 
  as 
  the 
  flower 
  is 
  

   mature. 
  This 
  leaves 
  the 
  

   stamens 
  and 
  pistil 
  ex- 
  

   posed 
  to 
  all 
  kinds 
  of 
  

   insect 
  visitors. 
  Insects 
  

   of 
  various 
  kinds 
  are 
  at- 
  

   tracted 
  by 
  the 
  sweet 
  

   odor 
  of 
  the 
  (lowers, 
  and 
  

   tiud 
  plenty 
  of 
  nectar 
  

   on 
  the 
  nectar 
  glands 
  

   which 
  stand 
  almost 
  un- 
  

   der 
  the 
  ovary 
  between 
  

   the 
  bases 
  of 
  the 
  fila- 
  

   ments 
  (fig. 
  120). 
  

  

  