1	"Spines or prickles present."	2
1	"Spines or prickles absent."	4
2	"Shrubs, vines or scramblers with simple recurved prickles; leaves bipinnate."	Caesalpinia
2	"Erect trees or shrubs with branched or simple straight spines; leaves bipinnate and/or pinnate."	3
3	"Spines usually >2 cm long; leaflets >10 mm long, not caducous; rachis terete; petals <5 mm long; pods >15 cm long."	Gleditsia
3	"Spines <2 cm long; leaflets <5 mm long, often caducous; rachis flattened, 2–3 mm wide; petals c. 10 mm long; pods <10 cm long."	Parkinsonia
4	"Leaves bipinnate."	5
4	"Leaves pinnately or palmately compound (leaflets 1-many) or rarely simple or reduced to phyllodes."	6
5	"Pods >20 cm long; stipules usually pinnate, 5–10 mm long; petals 2–3 cm long, stamens >7 cm long and strongly exserted."	Delonix
5	"Pods <10 cm long; stipules ovate, 3–5 mm long; petals and stamens 5–7 cm long, stamens not exserted."	Caesalpinia
6	"Leaves simple or apparently 1-foliolate, petiole about as long as lamina."	Barklya
6	"Leaves pinnately or palmately compound, or if reduced to phyllodes or apparently simple then petiole much shorter than lamina."	7
7	"Leaves imparipinnate; fertile anthers 3; style flat and petal-like, forming a pouch over the ovary."	Petalostylis
7	"Leaves paripinnate or reduced to phyllodes or leaflets 2 and venation palmate; other characters not as above."	8
8	"Leaflets 2, venation palmate; stigma peltate; stipe fused to floral tube."	Bauhinia
8	"Characters not as above, or if leaflets 2 then venation not palmate."	9
9	"Flowers predominantly unisexual, small (sepals <2 mm long), arranged in many-flowered catkin-like racemes; petals absent, flowers reddish."	Ceratonia
9	"Flowers bisexual, larger, in few- to many-flowered racemes; petals yellow, rarely spotted with red, >5 mm long."	10
10	"Floral bracteoles 2; stamens not bilaterally symmetric; pods elastically dehiscent with spirally coiled valves."	Chamaecrista
10	"Floral bracteoles 1 or absent; stamens bilaterally symmetric; pods never elastically dehiscent."	11
11	"Inflorescences terminal; bracteoles 1; longest anther filaments S-curved, anthers versatile, never beaked; tree, rare, confined to rainforest."	Cassia
11	"Inflorescences axillary; bracteoles absent; longest anther filaments C-curved, anthers basifixed, often some beaked; shrubs, subshrubs or herbs, widespread in open forest and shrubland."	Senna