1	"Leaves simple, modified to phyllodes, flattened and widened petioles"	"Acacia saligna"
1	"Leaves bipinnate"	2
2	"Stipules not spinescent; plants usually with curved or hooked prickles"	3
2	"Stipules spinescent, straight or, rarely, somewhat curved; prickles absent"	24
3	"Inflorescences capitate"	4
3	"Inflorescences spicate"	6
4	"Prickles solitary, scattered along the stems"	"Senegalia brevispica"
4	"Prickles in 3s or, if solitary, located at the nodes"	5
5	"Prickles in 3s; rachises of pinnae usually with a recurved prickle near the tip"	"Senegalia hamulosa"
5	"Prickles usually solitary; rachises of pinnae without a recurved prickle near the tip"	"Senegalia densispina"
6	"Prickles usually in pairs near the nodes, sometimes absent or almost so"	7
6	"Prickles in 3s or solitary near the nodes, almost always present"	12
7	"Pinnae with 1-2 pairs of leaflets; pedicels (0.5-)0.75-1.5 mm long"	"Senegalia mellifera"
7	"Pinnae with 3 or more pairs of leaflets; pedicels up to 0.5 mm long"	8
8	"Calyces puberulous; riverine trees"	"Senegalia rovumae"
8	"Calyces glabrous; plants shrubs or trees, of varied habitats"	9
9	"Bark yellowish, papery, flaking; pods puberulous"	10
9	"Bark not as above; pods glabrous or almost so"	11
10	"Leaflets 0.75 -2.5 mm wide; pods 0.9-1.1 cm wide"	"Senegalia ankokib"
10	"Leaflets 3.5-11 mm wide; pods 1.7-2 cm wide"	"Senegalia manubensis"
11	"Leaves with 2-3 pairs of pinnae; each pinna with 3-5 pairs of leaflets; plants shrubs or small trees"	"Senegalia laeta"
11	"Well-developed leaves with more than 3 pairs of pinnae, each pinna with more than 5 pairs of leaflets; plants large trees"	"Senegalia goetzii"
12	"Rachises of pinnae  with a recurved prickles on the lower surface at or near the tip"	"Senegalia hamulosa"
12	"Rachises of pinnae without a recurved prickle at or near the tip, sometimes the leaf rachises terminating in a prickle or with prickles on their lower surface"	13
13	"Filaments 13-18 mm long; leaves with 1 pair of pinnae, each pinna with 2-4 pairs of leaflets; leaflets 5-17 mm long, 3-13 mm wide"	"Senegalia ogadensis"
13	"Filaments less than 10 mm long; leaves and leaflets various, not as above in all respects"	14
14	"Petioles with a large flattened gland 1-3 mm in diameter"	15
14	"Petioles usually with glands less than 1 mm in diameter, occasionally up to 1.2"	16
15	"Petioles 13-28 mm long, the gland basal; pods 1.8-2.2 cm wide, densely puberulous"	"Senegalia condyloclada"
15	"Petioles 2-6 mm log, the gland at the point of attachment of the lowest pair of pinnae; pods 0.9-1 cm, wide, glabrous"	"Senegalia caraniana"
16	"Leaflets 8-19 mm long, 5-13 mm wide; pods (2-)3.2-4.8 cm wide with glabrous, thin, more or less crinkly valves"	"Senegalia zizyphispina"
16	"Leaflets smaller; pods less than 2 cm wide or, if wider, puberulous and not crinkly"	17
17	"Pinnae with 2-3 pairs of leaflets"	18
17	"Most pinnae with 4 or more pairs of spikelets"	19
18	"Pods densely and shortly appressed pubescent and with yellowish glands"	"Senegalia densispina"
18	"Pods glabrous"	"Senegalia somalensis"
19	"Flowers pink; inflorescences 12-18 mm long, with 7-15 flowers; pods completely glabrous"	"Senegalia moggii"
19	"Flowers white or cream; inflorescences longer, usually with 20 or more flowers; pods pubescent, at least near the base"	20
20	"Stems whip-like, with long slender branches from a basal cushion of short, vegetative branches"	21
20	"Stems not as above"	22
21	"Prickles in 3s; leaves with 3-8 pairs of pinnae; pods 1-2 cm wide"	"Senegalia cheilanthifolia"
21	"Prickles solitary; leaves with 1-2(-3) pairs of pinnae; pods (1.2-)1.4-1.9 cm wide"	"Senegalia flagellaris"
22	"Leaves with a prominent gland present between the lowest pair of pinnae; petiolar glands absent"	"Senegalia ochracea"
22	"Leaves lacking a gland between the lowest pair of pinnae; petiolar glands usually present"	23
23	"Bark grey, rough; nodes of branchlets less than 3 cm apart; pods mostly 2.5-8 cm long"	"Senegalia senegal"
23	"Bark yellowish-brown, flaking; nodes of branchlets mostly 3-4 cm apart; pods mostly 8-15 cm long"	"Senegalia circummarginate"
24	"Inflorescences spicate"	25
24	"inflorescences capitate"	27
25	"Stipular spines not inflated; leaf rachises with a conspicuous gland between each pair of pinnae; anthers without glands"	"Faidherbia albida"
25	"At least some stipular spines with inflated bases; leaf rachises without conspicuous glands; anthers with an apical gland that rapidly falls off"	26
26	"Inflated spines deeply constricted near the base; corollas 3-3.5 times as long as the calyces; pods straight; plants usually trees with a well-defined trunk"	"Vachellia bussei"
26	"Inflated spines not or only slightly constricted at the base; corollas 2-2.5 times as long as the calyces; pods curved; plants shrubs, branching from near the ground"	"Vachellia horrida"
27	"Some pairs of stipular spines fused at the base into an inflated, rounded or bilobed, ultimately woody structure"	28
27	"Stipular spines not inflated"	30
28	"Flowers white or cream; pods 4-7 cm long"	"Vachellia drepanospermum"
28	"Flowers bright yellow; pods mostly 7-20 cm long"	29
29	"Calyces 0.8-1.5 cm long"	"Vachellia zanzibarica"
29	"Calyces 2-2.5 cm long"	"Vachellia seyal"
30	"Flowers bright or golden yellow"	31
30	"Flowers white, cream, pale yellow, or pink"	32
31	"Bark or trunk yellowish, becoming powdery; epidermis of branchlets flaking off to expose a greenish-yellow inner layer; pods with thin valves"	"Vachellia xanothophloea"
31	"Bark of trunk not as above; epidermis of branchlets not flaking off; pods with thick valves"	"Vachellia nilotica"
32	"Many or all spines short and hooked or recurved, often intermixed with longer straight spines"	33
32	"All spines straight or nearly so, varying in length"	35
33	"Pods contorted or spirally twisted or, if straight or almost so, at least 12 cm long and leaves densely pubescent"	"Vachellia tortilis"
33	"Pods straight, usually less than 10 cm long; leaves sparsely pubescent"	34
34	"Branches usually with long straight and short curved spines intermixed; leaves with 1-9(-17) pairs of pinnae, usually at least some leaves with more than 4 pairs; plants trees, usually with well-marked trunks"	"Vachellia etbaica"
34	"Branches only with short hooked spines; leaves with 1-3 pairs of pinnae; plants usually shrubs that branch from near the base"	"Vachellia reficiens"
35	"Young branchlets villous with spreading hairs 0.75-3 mm long"	36
35	"Young branchlets glabrous or with shorter hairs, sometimes somewhat woolly"	37
36	"pods 6-12 cm long, 0.6-1 cm wide, dehiscent, coriaceous, attenuate at both the tip and the base; calyces and bracteoles glabrous or almost so"	"Vachellia paolii"
36	"Pods usually 2-4.5 cm long, 1-1.5 cm wide, indehiscent, thick and woody, less attenuate; calyces more or less pubescent outside; bracteoles ciliate or pubescent"	"Vachellia stuhlmannii"
37	"Leaflets 6-15 mm long and 3.5-9 mm wide; leaves with 2(-3) pairs of pinnae, the proximal pair much shorter than the distal pair"	"Vachellia walwalensis"
37	"Leaflets up to (7-) 9 mm long and 2(-4) mm wide; leaves usually with more than 2 pairs of pinnae but, if 2, then the proximal pair not much shorter than the distal pair"	38
38	"Corolla lobes glabrous or almost so on the outside"	39
38	"Corolla lobes conspicuously hairy on the outside"	40
39	"Pods distinctly curved"	"Vachellia robusta"
39	"Pods straight or almost so"	"Vachellia etbaica"
40	"Young branchlets, leaves, and pods clothed with a dense white woolly indumentum; leaflets so small and compressed that the pinnae resemble crenulate leaflets; seeds without areoles"	"Vachellia leucospira"
40	"Young branchlets, leaves, and pods glabrous to tomentose but not covered with a white indumentum; leaflets usually not as above; seeds with areoles"	41
41	"Pods with markedly thickened and woody valves, usually curved but sometimes almost straight; branchlets yellowish to purplish brown"	"Vachellia edgeworthii"
41	"Pods not markedly thickened and woody, usually straight, sometimes slightly curved; branchlets white, greyish-white, or yellowish-green"	"Vachellia oerfota"