1	"Filaments fused into filament column, generally with 5 free or fused, +- elaborate appendages abaxially; anthers fused into anther head around and fused to pistil head; pollen removed in pairs of pollinia; nectaries in stigmatic chambers (genera formerly treated as Asclepiadaceae)"	2
1	"Filaments free, unappendaged; anthers free, lying against, adherent to pistil head or not; pollen +- free, not removed in pollinia; nectaries 0 or near ovaries (genera formerly treated as Apocynaceae)"	6
2	"Filament column +- without appendages"	"Funastrum utahense"
2	"Filament column with appendages"	3
3	"Filament column appendages fused into 5-lobed, cup- or plate-like structure around anther head"	"Matelea {Matelea parvifolia}"
3	"Filament column appendages free"	4
4	"Filament column appendages hollow (possibly due to complete fusion of margins); ring of tissue at base of corolla present"	Funastrum
4	"Filament column appendages solid (margins converging, nearly meeting or not, not fused); ring of tissue at base of corolla 0"	5
5	"Filament column appendage margins converging but not nearly meeting abaxially; flowers in raceme- or panicle-like cymes; stem twining"	"Araujia {Araujia sericifera}"
5	"Filament column appendage margins converging and meeting or nearly meeting adaxially (to form hood); flowers in umbel-like cymes; stem prostrate to erect"	Asclepias
6	"Seed glabrous; stamens attached near top of corolla tube, near level of stigma"	7
6	"Seed with tuft of long hairs at 1 end; stamens attached at or near base of corolla tube, below level of stigma, or appearing so"	9
7	"Leaves alternate to subwhorled; plant erect"	"Amsonia {Amsonia tomentosa}"
7	"Leaves opposite to subopposite; plant erect or sprawling"	8
8	"Corolla pink, tube +- cylindric; plant erect"	"Catharanthus roseus"
8	"Corolla purple-blue (white), tube funnel-shaped; plant sprawling"	"Vinca {Vinca major}"
9	"Plant shrub, small tree; leaves generally whorled or subwhorled (opposite); nectaries 0; sap not milky"	"Nerium {Nerium oleander}"
9	"Plant perennial herb; leaves opposite; nectaries 5, free or fused; sap milky"	10
10	"Leaves, stems, roots not fleshy; flower < 8 mm, in generally >> 6-flowered cyme; nectaries 5, free"	Apocynum
10	"Leaves, stems, roots fleshy; flower > 15 mm, in 2--6-flowered cyme; nectaries 5, fused into a 5-lobed disk"	Cycladenia