﻿248 
  KEY 
  AND 
  FLORA 
  

  

  few 
  shorter 
  ones 
  at 
  the 
  base; 
  receptacle 
  naked 
  or 
  pitted. 
  Ray 
  

   flowers 
  yellow 
  or 
  orange, 
  pistillate 
  and 
  fertile 
  when 
  present 
  ; 
  

   disk 
  flowers 
  tubular, 
  bisexual. 
  Akenes 
  cylindrical 
  or 
  com- 
  

   pressed, 
  not 
  beaked 
  or 
  winged, 
  5-10-ribbed, 
  downy; 
  pappus 
  

   of 
  numerous 
  slender 
  white 
  hairs.* 
  

  

  1. 
  S. 
  glabellus 
  Poir. 
  BUTTERWEED. 
  Annual 
  ; 
  stem 
  erect, 
  ridged, 
  

   hollow, 
  often 
  woolly 
  when 
  young 
  and 
  becoming 
  smooth 
  with 
  age, 
  

   branched 
  above, 
  1-3 
  ft. 
  high. 
  Leaves 
  lyrate-pinnatifid, 
  thin, 
  the 
  lower 
  

   petioled, 
  the 
  upper 
  sessile. 
  Heads 
  radiate 
  in 
  a 
  terminal 
  corymb 
  ; 
  bracts 
  

   linear, 
  acute. 
  Ray 
  flowers 
  about 
  12, 
  yellow. 
  Akenes 
  slightly 
  rough- 
  

   hairy 
  on 
  the 
  angles; 
  pappus 
  rough, 
  longer 
  than 
  the 
  involucre. 
  Com- 
  

   mon 
  on 
  low 
  ground.* 
  

  

  2. 
  S. 
  aureus 
  L. 
  GOLDEN 
  RAGWEED. 
  Perennial; 
  stems 
  often 
  

   tufted, 
  erect, 
  slender, 
  woolly 
  when 
  young, 
  branched 
  above, 
  18-30 
  in. 
  

   high. 
  Lower 
  leaves 
  broadly 
  ovate, 
  obtuse 
  at 
  the 
  apex, 
  heart-shaped 
  

   at 
  the 
  base, 
  crenate, 
  long-petioled 
  ; 
  stem 
  leaves 
  lanceolate 
  and 
  often 
  

   pinnatifid, 
  the 
  upper 
  small 
  and 
  sessile. 
  Heads 
  radiate, 
  corymbed, 
  on 
  

   slender 
  peduncles. 
  Ray 
  flowers 
  8-12, 
  bright 
  yellow. 
  Akenes 
  smooth. 
  

   In 
  wet 
  soil 
  ; 
  very 
  variable.* 
  

  

  3. 
  S. 
  tomentosus 
  Michx. 
  WOOLLY 
  RAGWEED. 
  Perennial; 
  woolly 
  

   throughout 
  ; 
  stem 
  stout, 
  erect, 
  mostly 
  simple, 
  2-3 
  ft. 
  high. 
  Lower 
  

   leaves 
  ovate 
  to 
  oblong, 
  crenate 
  or 
  entire, 
  obtuse, 
  long-petioled 
  ; 
  stem 
  

   leaves 
  few, 
  elliptical 
  to 
  oblanceolate, 
  serrate 
  or 
  toothed, 
  acute, 
  sessile. 
  

   Heads 
  radiate, 
  | 
  in. 
  wide, 
  on 
  slender 
  peduncles 
  ; 
  bracts 
  narrow, 
  be- 
  

   coming 
  smooth. 
  Ray 
  flowers 
  12-15, 
  yellow. 
  Akenes 
  hairy. 
  In 
  damp 
  

   soil.* 
  

  

  XH. 
  CIRSIUM 
  Hill. 
  (CARDOTJS) 
  

  

  Biennial 
  or 
  perennial 
  ; 
  stem 
  erect, 
  simple 
  or 
  branched. 
  

   Leaves 
  alternate, 
  prickly, 
  often 
  forming 
  wings 
  on 
  the 
  stem. 
  

   Heads 
  discoid, 
  terminal 
  and 
  solitary 
  or 
  corymbed, 
  many-flow- 
  

   ered 
  ; 
  bracts 
  overlapping 
  in 
  many 
  series, 
  the 
  outer 
  shorter, 
  

   usually 
  spine-pointed 
  ; 
  receptacle 
  bristly. 
  Corollas 
  purplish 
  

   or 
  nearly 
  white, 
  the 
  tube 
  slender, 
  deeply 
  5-cleft. 
  Akenes 
  

   oblong, 
  4-angled, 
  smooth 
  or 
  ribbed; 
  pappus 
  of 
  numerous 
  

   simple 
  or 
  plumose 
  bristles. 
  [Most 
  of 
  our 
  commoner 
  species 
  

   blossom 
  in 
  the 
  late 
  summer 
  and 
  autumn.]* 
  

  

  1. 
  C. 
  spinosissimum 
  Scop. 
  YELLOW 
  THISTLE. 
  Biennial 
  or 
  perennial 
  ; 
  

   stem 
  erect, 
  stout, 
  woolly 
  when 
  young, 
  becoming 
  smooth, 
  often 
  purple, 
  

   branched, 
  1-3 
  ft. 
  high. 
  Leaves 
  pinnately 
  cut, 
  with 
  very 
  spiny 
  teeth, 
  

   mostly 
  sessile 
  and 
  clasping, 
  smooth 
  and 
  green 
  on 
  both 
  sides. 
  Heads 
  

  

  