1	"Leaves appearing simple"	2
1	"Leaves pinnate"	3
2	"‘Leaves’ 0.5-1.5 mm wide, glabrous to moderately hairy; pods strongly coiled (> 180 degrees)"	"Senna circinnata"
2	"‘Leaves’ 2.5-6.0 mm wide, very densely hairy; pods straight or curved through < 180 degrees"	"Senna phyllodinea"
3	"Glands absent from leaf rachis and petiole (although colleters may be present, see notes)"	4
3	"Gland or glands present on leaves, located either near base of petiole or between the leaflet pairs"	12
4	"Undamaged leaflets aristate, i.e. with a filamentous apex 1-5 mm long"	5
4	"Undamaged leaflets retuse, obtuse or mucronate (mucro < 1mm long)"	7
5	"Leaf rachis hairs 1-2.5 mm long; pods 2.5-4 cm long, glabrous"	"Senna notabilis"
5	"Leaf rachis hairs 0.3-1 mm long or absent; pods 4.5-10 cm long, with short spreading hairs"	6
6	"Floral bracts dark brown to black; petals 16-20 mm long; pods 7.5-10 cm long; colleters absent"	"Senna didymobotrya"
6	"Floral bracts green to pale yellow; petals 8-13 mm long; pods 4.5-7.5 cm long; colleters usually present between leaflet pairs"	"Senna venusta"
7	"Largest leaflets 33-70 mm wide"	8
7	"Largest leaflets 4.5-25 mm wide"	9
8	"Leaflet apex obtuse; leaves, rachis and pods covered by very short (c. 0.1 mm) patent hairs; pod with 2 lateral wings"	"Senna alata"
8	"Leaflet apex retuse; leaves, rachis and pods glabrous; pod not winged"	"Senna magnifolia"
9	"Leaf rachis and leaflets glabrous"	"Senna pleurocarpa"
9	"Leaf rachis hairy, lower surface of leaflets hairy"	10
10	"Largest leaflets 4.5-8.5 mm wide"	"Senna timorensis"
10	"Largest leaflets 9-25 mm wide"	11
11	"Leaflet apex acute, lower surface with spreading hairs; pods cylindrical, bearing 50-80 seeds"	"Senna spectabilis"
11	"Leaflet apex obtuse, lower surface with appressed hairs; pods flat, bearing 12-20 seeds"	"Senna siamea"
12	"Gland located near base of petiole"	13
12	"Gland located between lowest pair of leaflets (and sometimes between other leaflets), but absent from petiole"	18
13	"Leaflets moderately to densely hairy throughout"	14
13	"Leaflets glabrous or with sparse hairs on margins, midrib or petiolules"	15
14	"Hairs on leaf rachis 0.2-0.5 mm long; pods 5-8 cm long, straight; petiole gland erect"	"Senna sophera var. (40Mile Scrub J.R.Clarkson+ 6908)"
14	"Hairs on leaf rachis 1-1.5 mm long; pods 10-14 cm long, curved; petiole gland +/- appressed to petiole"	"Senna hirsuta"
15	"Leaflets narrow, 3.0-8.0 times longer than broad"	16
15	"Leaflets broad, 1.9-3.0 times longer than broad"	17
16	"Petiole gland clavate to ovoid, taller than wide; pods 5.5-7 cm long"	"Senna sophera var. sophera"
16	"Petiole gland oblate to dome-shaped, wider than tall; pods 3.5-5.5 cm long"	"Senna barclayana"
17	"Pods 5.3-8.0 cm long, cylindrical; petiole gland c. twice as wide as high; leaflet apex mostly obtuse, sometimes acute"	"Senna planitiicola"
17	"Pods 8.8-13.5 cm long, flattened; petiole gland c. as wide as high; leaflet apex acute to attenuate"	"Senna occidentalis"
18	"Leaflets glabrous or with hairs confined to lamina base, margins and/or midrib"	19
18	"Lower leaflet surface sparsely to densely hairy throughout"	29
19	"Leaflets narrow, more than 3 times longer than wide"	20
19	"Leaflets broad, less than 3 times longer than wide"	24
20	"Glands small, flat or dome-like, < 0.5 mm long; leaves glutinous or pruinose"	"Senna glutinosa"
20	"Gland(s) erect, cylindrical to clavate, 1-2.5 mm long; leaves neither glutinous nor pruinose"	21
21	"Leaflets linear, 10-30 times longer than wide"	"Senna aciphylla"
21	"Leaflets lanceolate to elliptical, 3-7 times longer than wide"	22
22	"Leaves with 4-5 pairs of leaflets; pods strongly curved, 8-11 mm wide; leaflet apex minutely retuse"	"Senna costata"
22	"Leaves with 8-13 pairs of leaflets; pods straight or slightly curved, 4-6 mm wide; leaflet apex obtuse or mucronate"	23
23	"Gland present between the lowest pair of leaflets only; pedicels 5-12 mm long at anthesis; petals 8-13 mm long; leaflet apex obtuse"	"Senna coronilloides"
23	"Gland present between (at least) the lowest three pairs of leaflets; pedicels 15-22 mm long at anthesis; petals 16-20 mm long; leaflet apex mucronate"	"Senna barronfieldii"
24	"Leaves with 1 or 2 pairs of leaflets, rachis glands 0.5-1 mm long; mature pods 2-3.5 cm long"	"Senna leptoclada"
24	"Leaves with 3-8 pairs of leaflets, rachis glands 1.3-2.6 mm long; mature pods 6-17 cm long"	25
25	"Gland(s) on leaf rachis ovoid to conical; fertile stamens 6-7; pods cylindrical"	26
25	"Glands on leaf rachis clavate; fertile stamens 10; pods flat"	27
26	"Gland present between most leaflet pairs; longest leaflets 50-90 mm long, apex acute"	"Senna septemtrionalis"
26	"Gland present between lowest leaflet pair only; longest leaflets 18-40 mm, apex obtuse"	"Senna pendula var. glabrata"
27	"Mature pods 5-8 mm wide"	"Senna acclinis"
27	"Mature pods 9-15 mm wide"	28
28	"Leaves with 4-5 pairs of leaflets; largest leaflets 47-110 mm long, midrib glabrous on lower surface"	"Senna sulfurea"
28	"Leaves with 5-8 pairs of leaflets; largest leaflets 34-50 mm long, midrib hairy on lower surface"	"Senna surattensis"
29	"Rachis gland(s) flat to mounded or dome-like, wider than long"	"Senna artemisioides"
29	"Rachis gland(s) cylindrical to clavate, much longer than wide"	30
30	"Leaves with 1-2(-3) pairs of leaflets; glands densely hairy; pods 2-4 cm long"	31
30	"Leaves with 3-8 pairs of leaflets; glands glabrous; pods 5-17 cm long"	32
31	"Stipules acicular, caducous"	"Senna oligoclada"
31	"Stipules cordate or auriculate, persistent"	"Senna cladophylla"
32	"Leaves almost always with 3 pairs of leaflets; pods cylindrical, 3-4 mm wide, curved"	33
32	"Leaves 4-8 pairs of leaflets; pods flat, 8-13 mm wide, straight"	34
33	"Anthers beaked; seed areole oblique"	"Senna obtusifolia"
33	"Anthers truncate; seed areole longitudinal"	"Senna tora"
34	"Upper leaf surface often sparsely to moderately hairy"	"Senna gaudichaudii"
34	"Upper leaf surface glabrous"	"Senna surattensis"