Pipeworts

Eriocaulon

1 Receptacle and/or base of flowers copiously hairy; some of perianth parts with chalk white hairs; heads overall appearing white, 5-20mm
   in diameter when in full flower or fruit.
  2 Heads hard (feeling hard and knotty when squeezed between finger and thumb); leaves dark green, the tip acute to obtuse; scape sheaths
   shorter than most leaves; involucral bracts straw-colored, the apex acute; receptacular bracteoles pale, the apex narrowly acuminate;
   pistillate flower petals adaxially glabrescent; terminal cells of club-shaped hairs of the perianth whitened, the basal cells often uncongested
   and transparent............................................................................................................................................................ Ten-angled Pipewort
  2 Heads soft (easily compressed when fresh between finger and thumb); leaves pale green, the tip attenuate-subulate; scape sheaths longer
   than most leaves; involucral bracts gray or dark, the apex rounded or obtuse; receptacular bracteoles gray to dark gray, the apex acute;
   pistillate flower petals adaxially villous; all cells of club-shaped hairs on perianth white........................................... Flattened Pipewort
1 Receptacle and/or base of flowers glabrous or sparingly hairy; receptacular bracteoles and/or perianth parts glabrous or hairy, the hairs
   club-shaped, clear or white; heads dark gray or white, 3-10 mm in diameter when in full flower or fruit.
  3 Heads 4-10mm in diameter when in full flower or fruit; outer involucral bracts usually reflexed, obscured by bracteoles and
   flowers.............................................................................................................................................................................. Common Pipewort
  3 Heads 3-4mm in diameter when in full flower or fruit; outer involucral bracts neither reflexed nor obscured by bracteoles and
   flowers............................................................................................................................................................................... Parker's Pipewort