:

:
Plant
  habit
   shrubs
   aquatic & OBL wetland species
Leaves
  arrangement/phyllotaxy
   alternate
   opposite
   whorled
  leaf attachment
   sessile or nearly so
   leaf stalk (petiole) clearly present
  leaf(let) base
   attenuate
   clasping
   cordate
   cuneate
   obtuse
   rounded
  broadest point of leaf (leaflet)
   broadest at middle
   broadest below middle
Flower
  principal flower color
   white or cream
   purple
   green
   yellow
   orange
   red
   pink
   brown
  corolla (petal) fusion
   petals separate
   fused, at least toward base

Asclepias of Colorado

Nabhan, Buckley, and Fishbein
Species Count: 17

Apocynaceae