1	Mature plants with phyllodes		(2)
+	Mature plants with normal leaves		(6)
2 (1)	Inflorescence a spike		(3)
+	Inflorescence a head		(4)
3 (2)	Phyllodes curved, 1.5-5 cm broad; fruit circinately coiled		Acacia auriculiformis
+	Phyllodes almost straight, 1 cm or less broad; fruit straight.		Acacia aneura
4 (2)	Phyllode with a prominent midrib		Acacia saligna
+	Phyllode without any midrib (a number of veins present, running parallel to the longitu-dinal axis of the phyllode)		(5)
5 (4)	Phyllode c. 1-2.5 cm wide, fruit c. 8 mm broad, not torulose		Acacia melanoxylon
+	Phyllode 12 mm or less wide; fruit c. 3-4 mm broad, slightly torulose		Acacia homalophylla
6 (1)	Inflorescence a spike		(7)
+	Inflorescence a head		(12)
7 (6)	Spiny stipules very thick and horny		Acacia cornigera
+	Spiny stipules slender		(8)
8 (7)	Pod bright orange		Acacia albida
+	Pod not bright orange		(9)
9 (8)	Pinnae 10 pairs or more (calyx and corolla villous Or pubescent)		Acacia catechu
+	Pinnae 5 pairs or fewer		(10)
10 (9)	Prickles in threes; pinnae 3-5 pairs		Acacia senegal
+	Prickles in twos; pinnae 2-3 pairs		(11)
11 (10)	Corolla 3 times the size of calyx; pod ensiform, not beaked		Acacia mellifera
+	Corolla 2 times the size of calyx; pod beaked, (base attenuated into a distinct stipe.)		Acacia modesta
12 (6)	Internodes provided with prickles		(13)
+	Internodes without prickles		(14)
13 (12)	Flower heads in bud pubescent; young pod velvety		Acacia torta
+	Flower heads in bud glabrous; young pod pubescent but not velvety		Acacia gageana
14 (12)	Stipules not spiny, (leaf stalk decurrent)		(15)
+	Stipules spiny		(16)
15 (14)	Leaflets 5-12 mm long		Acacia decurrens
+	Leaflets 1.5-4 mm long		Acacia mearnsii
16 (14)	Spiny stipules become very thick and horn-like		(17)
+	Spiny stipules do not become thick and horn-like		(19)
17 (16)	Young branches without glands		Acacia sphaerocephala
+	Young branches with numerous reddish sessile glands		(18)
18 (17)	Pairs of spines (ant galls) neither fused together nor bilobed		Acacia seyal var. seyal
+	Pairs of spines fused at the base into ant galls, often bilobed		Acacia seyal var. fistula
19 (16)	Heads generally terminal, paniculate		Acacia leucophloea
+	Heads axillary, pedunculate		(20)
20 (19)	Ovary pilose		(21)
+	Ovary glabrous		(28)
21 (20)	Pod contorted or spirally twisted		Acacia tortilis
+	Pod not spirally twisted		(22)
22 (21)	Fruit straight margined, falcate or slightly crenate		(27)
+	Fruit moniliform		(23)
23 (22)	Pod narrowly and regularly constricted between seeds		(25)
+	Pod not narrowly and regularly constricted between seeds		(24)
24 (23)	Pod slightly constricted between seeds		Acacia nilotica ssp. astringens
+	Margins of pod straight or slightly crenate		Acacia nilotica ssp. subalata
25 (23)	Plant cupressiform in appearance		Acacia nilotica ssp. cupressiformis
+	Plant not cupressiform in appearance		(26)
26 (25)	Pod whitish or grey tomentellous		Acacia nilotica ssp. indica
+	Pod glabrous, not tomentellous		Acacia nilotica ssp. nilotica
27 (22)	Plant hemispherical		Acacia nilotica ssp. hemispherica
+	Plant not hemispherical		Acacia sieberiana
28 (20)	Peduncle without a distinct joint		(29)
+	Peduncle with a distinct joint		(30)
29 (28)	Pod hard woody and swollen, with a curved beak-like structure at the tip		Acacia farnesiana
+	Pod flat, papery, with only an apical curved mucro		Acacia filicioides
30 (28)	Pod long and narrow, 7.5-15.0 cm long. c. 5-9.0 mm broad, sutures undulate		(31)
+	Pod short and broad, 5-7.5 cm long, c. 8-17 mm broad, sutures straight		Acacia jacquemontii
31 (30)	Peduncle c. 1.0-1.8 cm long; pinnae 1-4 pairs		Acacia hydaspica
+	Peduncle c. 2.5 cm long; pinnae 2-8 pairs		Acacia eburnea