﻿240 
  

  

  KEY 
  AND 
  FLORA 
  

  

  pollination. 
  The 
  genera 
  of 
  the 
  northern 
  United 
  States 
  are 
  

   divided 
  into 
  two 
  suborders 
  : 
  I. 
  TUBULIFLOK^ 
  corolla 
  of 
  

   the 
  bisexual 
  flowers 
  tubular 
  and 
  5-lobed 
  ; 
  II. 
  LIGULIFLOK^E, 
  

   corollas 
  all 
  strap-shaped 
  and 
  flowers 
  all 
  bisexual. 
  

  

  FIG. 
  30. 
  Akenes 
  with 
  various 
  types 
  of 
  pappus 
  

  

  A, 
  Rudbeckia, 
  pappus 
  wanting; 
  B, 
  Cichorium, 
  pappus 
  a 
  crown 
  of 
  fine 
  scales; 
  

   C, 
  Coreopsis, 
  pappus 
  of 
  2 
  small 
  scales; 
  D, 
  Helenium, 
  pappus 
  a 
  crown 
  of 
  

   conspicuous 
  scales; 
  E, 
  Cirsium, 
  pappus 
  a 
  tuft 
  of 
  plumose 
  hairs; 
  F, 
  Lac- 
  

   tuca, 
  pappus 
  borne 
  on 
  a 
  long 
  beak 
  

  

  I. 
  TUBULIFLORJE 
  1 
  

  

  Corollas 
  some 
  or 
  all 
  of 
  them 
  tubular. 
  

  

  Rays 
  white, 
  pink, 
  or 
  purplish. 
  

  

  Rays 
  many 
  ; 
  akenesflat; 
  pappus 
  wanting 
  ; 
  low 
  herbs. 
  Bellis, 
  I 
  

   Rays 
  many 
  ; 
  akenes 
  cylindrical 
  or 
  winged, 
  grooved 
  ; 
  pappus 
  

  

  wanting; 
  tall 
  herbs 
  or 
  shrubby. 
  Chrysanthemum, 
  X 
  

  

  Rays 
  many 
  ; 
  akenes 
  flat 
  ; 
  pappus 
  of 
  an 
  outer 
  row 
  of 
  minute 
  

  

  scales 
  and 
  an 
  inner 
  row 
  of 
  delicate 
  bristles. 
  Erigeron, 
  II 
  

   Rays 
  many; 
  akenes 
  cylindrical 
  or 
  ribbed; 
  pappus 
  wanting; 
  

  

  strong-scented, 
  branching 
  herbs. 
  Anthemis, 
  IX 
  

  

  Rays 
  few. 
  Achillea, 
  VIII 
  

  

  1 
  The 
  characters 
  in 
  this 
  key 
  are 
  not 
  necessarily 
  true 
  of 
  all 
  species 
  in 
  the 
  

   genera 
  referred 
  to, 
  but 
  only 
  of 
  those 
  described 
  below, 
  

  

  