1	"Mature leaves appearing simple (phyllodes); flowers in heads or spikes and these 1–several in each axil or in racemes or panicles"	Acacia
1	"Mature leaves bipinnate"	2
2	"Leaf axes lacking extrafloral nectaries"	3
2	"Leaf axes with extrafloral nectaries"	4
3	"Stamens 10 in perfect flowers; basal flowers sterile with elongate flat filaments; pod opening on both sutures"	Neptunia
3	"Stamens as many as or twice as many as corolla lobes; basal flowers not sterile; pod dehiscing in 1-seeded segments, the marginal portion persistent"	Mimosa
4	"Flowers in distinct spikes or spicate racemes"	5
4	"Flowers in rounded to oblong heads or, if spicate, then some basal flowers imperfect"	10
5	"Stamens 10, free"	6
5	"Stamens numerous, free or united"	7
6	"Pod indehiscent, filled with pulp surrounding seeds; most or all flowers perfect"	Prosopis
6	"Pod not as above; only apical flowers perfect"	"Dichrostachys: Dichrostachys spicata"
7	"Stamens united basally"	"Paraserianthes: Paraserianthes lophantha subsp. lophantha"
7	"Stamens free, rarely basally united"	8
8	"Inflorescences elongated racemes (>1 cm long) or paniculate; stipules inconspicuous; prickles absent"	Acacia
8	"Inflorescences simple (peduncles solitary or clustered) or in very short racemes <5 mm long"	9
9	"Peduncles with an involucel of bracts above the base (sometimes at apex of peduncles and hidden by flowers); stipules spinescent, at least on young plants; prickles absent"	Vachellia
9	"Peduncles without an involucel of bracts; stipules not spinose (but stems sometimes armed with non-stipular prickles)"	Acacia
10	"Peduncles bearing 2 conspicuous, ±foliaceous bracts; pod nearly circular to broadly oblong, stipitate"	Neptunia
10	"Peduncles lacking such bracts; pod variable in form"	11
11	"Pod dehiscing in 1-seeded, indehiscent segments"	"Cathormion: Cathormion umbellatum subsp. moniliforme"
11	"Pod dehiscing otherwise"	12
12	"Stamens 5 or 10, free; petals free"	13
12	"Stamens numerous, free or united"	14
13	"Flowers all perfect; pod broadly oblong or linear-oblong, 15–27 mm wide"	"Leucaena: Leucaena leucocephala subsp. leucocephala"
13	"Flowers near base of head male or sterile; pod narrowly linear, flat, to 4 mm wide"	"Desmanthus: Desmanthus virgatus"
14	"Stamens united at least basally"	Albizia
14	"Stamens free"	15
15	"Inflorescences elongated racemes (>1 cm long) or paniculate; stipules inconspicuous; prickles absent"	Acacia
15	"Inflorescences simple (peduncles solitary or clustered) or in very short racemes <5 mm long"	16
16	"Peduncles with an involucel of bracts above the base (sometimes at apex of peduncles and hidden by flowers); stipules spinescent, at least on young plants; prickles absent"	Vachellia
16	"Peduncles without an involucel of bracts; stipules not spinose (but stems sometimes armed with non-stipular prickles)"	Acacia