1	"Leaves in mature plants opposite, stipulate"	2
1	"Leaves in mature plants alternate or sometimes appearing fascicled, stipulate, or leaves reduced to exstipulate scales and apparently absent"	4
2	"Standard petal shorter than the wing and keel petals; petals green, greenish-yellow, pale salmon to dull red or deep burgundy; flowers pendulous, the apex of the keel facing the ground; leaf lamina broadly ovate-cordate or triangular to hastate- lanceolate or almost linear"	"Bossiaea dentata"
2	"Standard petal as long as or longer than the wing and keel petals; petals yellow and red; flowers not pendulous, the apex of the keel not facing the ground; leaf lamina semi-orbicular to semi-reniform, depressed ovate or broadly ovate"	3
3	"Leaf-lamina depressed ovate or broadly ovate to semi-orbicular, angular, margin pungent-pointed or denticulate, the midrib terminating in a pungent point"	"Bossiaea aquifolium"
3	"Leaf-lamina semi-orbicular to semi-reniform, margin minutely denticulate, emarginate apically or midrib ending in a short mucro but not extending into a distinct pungent point"	"Bossiaea webbii"
4	"Leaves in mature plants alternate or sometimes appearing fascicled, stipulate, occasionally leaves few, inconspicuous, mostly confined to the new growth and soon caducous; branches terete, oval and angled or occasionally flattened and/or winged but if so the leaves stipulate"	5
4	"Leaves in mature plants reduced to exstipulate scales; branches (cladodes) usually flattened and winged"	33
5	"Ovary densely villous throughout"	6
5	"Ovary glabrous throughout or with scattered hairs on one or both sutures and occasionally with a few scattered hairs on the surface of the valves"	13
6	"The 2 upper calyx-lobes obovate, greatly enlarged relative to the 3 lower lobes, free on the upper side almost to the base, about as long as the standard petal; leaf-lamina 2.3–6.0 mm long"	"Bossiaea spinosa"
6	"The 2 upper calyx-lobes not obovate, not greatly enlarged relative to the 3 lower lobes and not free on the upper side almost to the base, much shorter than the standard petal; leaf-lamina (2.7–) 5–60 mm long"	7
7	"Prostrate spreading subshrub, rooting at nodes of the prostrate branches; tap-roots dauciform; standard petal 7–9 mm long"	"Bossiaea reptans"
7	"Erect shrub; tap roots not dauciform; standard petal 8–20 mm long"	8
8	"Abbreviated lateral shoots present and usually terminating in a pungent point; divaricately branched rigid shrub; petiole 0.3–0.6 mm long; 3 lower calyx-lobes 2.3– 3.7 mm long, about as long as the calyx-tube"	"Bossiaea divaricata"
8	"Abbreviated lateral shoots absent or, if present, not terminating in a pungent point; shrub not divaricately branched; petiole 0.8–4.0 mm long; 3 lower calyx-lobes 3.5– 10 mm long, longer than the calyx-tube"	9
9	"Leaf-lamina 1.5–6.0 mm wide, typically narrow-oblong or linear; venation simple craspedodromous (secondary veins inserted almost at right angles to the midrib and all of the secondary veins and their branches terminating at the margin, the branches not joining adjacent veins before reaching the margin); apices of keel petals seldom fimbriate"	10
9	"Leaf-lamina (2-) 5–38 mm wide, typically ovate; venation semicraspedodromous (secondary veins branching just before they reach the margin and joining adjacent veins before one arm terminates at the margin); apices of keels invariably minutely fimbriate"	11
10	"Leaves widely spaced, not overlapping; flowers paired, subtended by 6-8 imbricate bracts"	"Bossiaea moylei"
10	"Leaves not widely spaced, overlapping; flowers solitary, subtended by 2 bracts"	"Bossiaea eriocarpa"
11	"Leaves narrow lanceolate, 40-70 mm long, 11-17 mm wide; single stemmed, lignotuber absent"	"Bossiaea angustifolia"
11	"Leaves oblong to ovate, 10-40 mm long, 5-38 mm wide; multi-stemmed, lignotuber present"	12
12	"Mature stems 3-4 mm wide; leaves ovate, 21-40 mm long, 21-33 mm wide; flowers paired; calyx densely sericeous"	"Bossiaea ornata"
12	"Mature stems slender, 1-2 mm wide; leaves oblong to ovate, 10-25 mm long, 5-10 mm wide; flowers solitary; calyx glabrous (rarely sparsely hairy). margins ciliate"	"Bossiaea lalagoides"
13	"Keel petals glabrous or with occasional scattered hairs apically in the sinus"	14
13	"Keel petals densely woolly-pubescent apically in the sinus"	17
14	"Leaves distinctly ovate-cordate, the margins minutely and irregularly crenulate; the 2 outer basal bracts rigid, coriaceous, together almost cupular; pods scarcely longer than wide"	"Bossiaea pulchella"
14	"Leaves not distinctly ovate-cordate, the margins entire; the 2 outer basal bracts not as above; pods distinctly longer than wide"	15
15	"Calyx glabrous apart from marginal cilia on the lobes; young branchlets terete to oval or slightly flattened but not winged, covered with a white waxy outer layer that rapidly exfoliates to reveal a pitted green inner layer; leaves usually confined to the young growth, mostly soon caducous and the plants superficially apparently leafless"	"Bossiaea eremaea"
15	"Calyx sparingly to densely clothed with appressed to spreading hairs; young branchlets winged or not winged, lacking a white waxy outer layer that exfoliates to reveal a green inner surface; leaves persisting or caducous, sometimes plants almost leafless but then the young branchlets winged"	16
16	"Erect slender shrub; young stems terete or oval in section to slightly flattened, up to 2 mm wide, not incised at the nodes; leaf-lamina oblong, linear- oblong to obovate-oblong; stipules exceeding the petiole; flowers on pedicels 7–14 mm long"	"Bossiaea disticha"
16	"Lax weak-stemmed shrub, the stems often sprawling and only erect when supported by surrounding vegetation; young stems flattened and winged, 1.5–7.0 mm wide, incised at the nodes; leaf-lamina rotund, obovate or obovate- to elliptic-oblong; stipules usually shorter than the petiole; flowers on pedicels 2–5 mm long"	"Bossiaea praetermissa"
17	"Unarmed shrub, the abbreviated lateral shoots, if present, not terminating in a pungent point"	18
17	"Spinescent shrub, the abbreviated lateral shoots terminating in a pungent point"	22
18	"Calyx densely clothed with short spreading hairs; pedicels 2–5 mm long, clothed with short spreading hairs; leaves often absent at the nodes, the lamina represented by a linear terete or subterete appendage that extends beyond the two adjacent stipules"	"Bossiaea praetermissa"
18	"Calyx glabrous or with scattered appressed hairs; pedicels (3–) 5–25 mm long, glabrous to densely pubescent; leaf lamina not represented by a terete or subterete appendage"	19
19	"Lax weak-stemmed subshrub to 0.5 m high with wiry trailing or sprawling stems; stem extremities somewhat flattened and up to 2 mm wide"	"Bossiaea modesta"
19	"Shrub to 3 m high, stems not wiry, trailing or sprawling, or, if sprawling, flattened, winged and 1.5–10 mm wide"	20
20	"Keel petals uniformly greenish-yellow; standard petal 12–16 mm long"	"Bossiaea laxa"
20	"Keel petals suffused externally with red or dark red apically or throughout; standard petal 6.6–12.2 mm long"	21
21	"Young stems oval in section to slightly flattened, up to 2 mm wide, not incised at the nodes; calyx glabrous or with scattered appressed hairs; pedicels sparingly to densely pubescent; pods 0.9–1.7 cm long"	"Bossiaea linophylla"
21	"Young stems flattened, winged, 1.5–10 mm wide, incised at the nodes; calyx glabrous; pedicels glabrous or sparingly pubescent; pods (2.0) 2.5–3.8 cm long"	"Bossiaea rufa"
22	"Flowers pendulous; standard petal (9.5–)13.0–17.4 mm long; keel petals about as long as the standard"	"Bossiaea preissii"
22	"Flowers not pendulous; standard petal up to 13.0 mm long; keel petals usually shorter than the standard"	23
23	"Young branchlets sparingly to densely clothed with appressed to spreading hairs; lower surface of leaves sparingly to densely clothed with straight appressed or crinkled slightly spreading hairs, seldom glabrous"	24
23	"Young branchlets glabrous or with occasional scattered hairs (apart from hairs at the apices of bracts in the leaf axils); lower surface of leaves glabrous or almost so"	29
24	"Pedicels filiform, 8–13 mm long, usually inserted well above the axils; keel petals pale greenish-yellow"	"Bossiaea peduncularis"
24	"Pedicels slender to stout, 2.0–7.2 mm long, usually axillary; keel petals yellow, yellow and red, purple or pinkish-red"	25
25	"Calyx glabrous externally apart from hairs on the margins of the lobes"	26
25	"Calyx sparingly to densely pubescent externally"	27
26	"Bracteoles usually rapidly caducous and leaving 2 prominent raised opposite or subopposite scars on the pedicel; leaf-lamina oblong to narrowly obovate-oblong, (1.5–) 3–7 (–10) mm long, arching down on either side of the midrib, the margins slightly recurved or revolute to such an extent that only the midrib is visible below or the margins meeting and the lamina almost terete, with apex rounded or obtuse, not glaucous, upper surface shiny"	"Bossiaea smithiorum"
26	"Bracteoles persisting; leaf-lamina obovate, slightly obtrullate, obovate-oblong, elliptic or oval, 1.2–3.9 mm long, usually flat to ∨-shaped in section, with apex often depressed-retuse, glaucous, upper surface not shiny"	"Bossiaea barbarae"
27	"Leaf-lamina 1.1–4.0 mm wide, apex emarginate or truncate; young branchlets oval in section to flattened (confined to the coastal limestone plain and some off-shore islands)"	"Bossiaea calcicola"
27	"Leaf-lamina 0.8–2.0 mm wide, apex rounded or depressed-retuse; young branchlets terete to oval in section and slightly angular (absent from the coastal limestone plain and off-shore islands, an inland species)"	28
28	"Leaf-lamina oblong or narrowly obovate-oblong, 0.8–1.4 mm wide, lamina sloping down on either side of the midrib so upper surface usually slightly convex in section, green, apex rounded, upper surface shiny"	"Bossiaea aurantiaca"
28	"Leaf-lamina obovate, slightly obtrullate, obovate-oblong, elliptic or oval, 0.9–2.0 mm wide, usually flat to ∨-shaped in section, glaucous, apex rounded or depressed- retuse, upper surface not shiny"	"Bossiaea barbarae"
29	"Leaves inconspicuous, few, confined to the young growth and caducous, the plants superficially apparently leafless"	"Bossiaea arcuata"
29	"Leaves conspicuous, numerous, not confined to the young growth, not caducous, the plants obviously ‘leafy’"	30
30	"Young branchlets oval in section to flattened and narrowly winged; petiole typically attached almost at right angles to the leaf-lamina (so that the lamina tends to be held in a different plane to the petiole)"	"Bossiaea spinescens"
30	"Young branchlets terete to oval in section and angled but not flattened and narrowly winged; petiole not attached almost at right angles to the base of the leaf-lamina"	31
31	"Calyx and pedicels dark red or purplish; leaf-lamina flat or ∨-shaped to almost conduplicate"	"Bossiaea atrata"
31	"Calyx and pedicels green or suffused with red or pinkish-red; leaf-lamina flat or convex in section (sloping down on either side of the midrib)"	32
32	"Pedicels filiform, 3.5–11.0 mm long, usually longer than the leaves; leaves 1.0–1.3 (–1.6) mm wide, glaucous; compact dense intricately branched shrub (plants occur on or near the perimeter of salt lakes)"	"Bossiaea concinna"
32	"Pedicels stout, 2.0–5.0 mm long, shorter than, as long as, or just exceeding the leaves; leaves 1.2–2.0 (–3.5) mm wide, not glaucous; open shrubs with many slender sparingly branched stems arising from the base (plants confined to the Murchison River gorge)"	"Bossiaea inundata"
33	"Ultimate cladodes very broadly winged, 10–65 mm wide, wings incised at the nodes, the lobes projecting laterally or forwards and usually with an acute pungent apex"	"Bossiaea bossiaeoides"
33	"Ultimate cladodes winged or scarcely winged, 1–10 mm wide, when present wings incised at the nodes but lobes lacking an acute or pungent apex"	34
34	"Flowers pendulous; standard much shorter than the keel petals; keel petals 13.5–26.0 mm long"	35
34	"Flowers not pendulous, the standard petal facing perpendicularly like a banner; standard as long as or longer than the keel petals; keel petals 6–12 mm long"	36
35	"Bracteoles caducous, basal; pedicels glabrous or almost so; standard 18–19 mm long, uniformly red or salmon-pink (rarely yellow) externally or occasionally suffused with orange"	"Bossiaea walkeri"
35	"Bracteoles persistent, attached towards the middle of the pedicel; pedicels pubescent below the bracteoles; standard 10–14.4 mm long, deep yellow or orange-yellow externally and sometimes suffused with dark red or purple apically"	"Bossiaea cucullata"
36	"Ovary glabrous or with scattered hairs along one or both sutures and occasionally also with scattered hairs on the surface of the valves"	37
36	"Ovary densely pubescent throughout or densely pubescent except along the lateral margins"	43
37	"Bracteoles rapidly caducous"	38
37	"Bracteoles persistent until at least the young pods start to develop"	39
38	"Ultimate branches of cladodes 0.7–2.2 mm wide; keel petals pale greenish- yellow throughout or sometimes with a reddish-brown longitudinal striation towards the lower margin and more or less parallel to it; standard yellow internally with a reddish-brown throat from which red-brown striations radiate into the lamina (favours deep sand above the samphire zone near the perimeter of salt lakes)"	"Bossiaea halophila"
38	"Ultimate branches of cladodes 1.5–10.0 mm wide; keel petals green basally, dark red apically; standard deep orange-yellow internally with a deep purplish-red or reddish-pink basal horseshoe-shaped flare around a yellow throat (favours moist situations or amongst rocks along streams and near swamps)"	"Bossiaea rufa"
39	"A linear terete or subterete appendage present in the axil of the scale leaves [stipules] at each node"	"Bossiaea praetermissa"
39	"A linear terete or subterete appendage absent from the axil of the scale leaves at each node"	40
40	"Ovary with coarse hairs along each suture; calyx sparingly to densely clothed with appressed or spreading hairs"	"Bossiaea saxosa"
40	"Ovary glabrous; calyx glabrous throughout apart from hairs on the margins of the lobes or with occasional scattered hairs"	41
41	"Standard petal externally red or reddish-brown with yellow longitudinal striations radiating from the base; keel petals deep red"	"Bossiaea oxyclada"
41	"Standard petal externally yellow throughout or with faint red longitudinal striations radiating from the base; keel petals yellow or greenish-yellow"	42
42	"Low compact dense spreading shrub to 0.5 m high; ultimate branches of cladodes terete to oval in section or slightly flattened, 1.0–1.5 mm wide, scarcely or narrowly winged; pods 1.5–2.4 cm long"	"Bossiaea leptacantha"
42	"Lax spreading or semi-prostrate shrub to 0.7 m high; ultimate branches of cladodes flattened, 0.7–8.3 mm wide, winged; pods 2.7–4.8 cm long"	"Bossiaea barrettiorum"
43	"Bracteoles usually rapidly caducous; ovary densely pubescent throughout"	"Bossiaea celata"
43	"Bracteoles persistent at least until the young pods develop; ovary densely pubescent except along the lateral margins"	44
44	"Branches distinctly flexuose; calyx densely clothed with appressed or spreading hairs 0.3–0.5 mm long; keel petals greenish-yellow basally, deep pinkish-red apically"	"Bossiaea flexuosa"
44	"Branches not or occasionally slightly flexuose; calyx densely clothed with appressed or slightly spreading hairs up to 0.3 mm long; keel petals pale greenish-yellow throughout or orange-red basally"	"Bossiaea simulata"