1	"Cauline leaves alternate; flower unisexual, plants monoecious or dioecious"	Amaranthus
1	"Cauline leaves generally opposite; flower bisexual"	2
2	"Hairs forked"	Tidestromia
2	"Hairs simple or 0"	3
3	"Leaves fleshy; inflorescence axillary, flowers 1--3"	Nitrophila
3	"Leaves not fleshy; inflorescence axillary, terminal, or both, flowers > 3"	4
4	"Perianth parts free"	Alternanthera
4	"Perianth parts fused >= 1/2"	"Guilleminea {Guilleminea densa var. aggregata}"