Leaves usually imparipinnate; leaflets few to many, occasionally reduced or absent, margins entire; stipules present and usually with a prominent abaxial ridge, stipels usually absent.
Inflorescences axillary racemes; bracts present, bracteoles small. Calyx ± campanulate, teeth ± equal, or upper 2 shorter. Corolla mostly purple, occasionally white, pink, yellow, orange or red; standard usually longer than wings, sometimes longer than the keel. Stamens diadelphous, of alternating lengths; anthers uniform. Ovary usually ± stipitate; style incurved, usually bearded lengthwise along the upper part and often with a tuft of hairs behind the stigma; stigma terminal or subterminal.
Pod usually dehiscent, sometimes inflated, 1-locular or longitudinally 2-locular; seeds few to numerous, aril not present.
| | Key to the species | |
| 1 | Stems hairy with hairs either basifixed or laterally attached at base, or stems glabrous | 2 |
| Stems hairy with hairs symmetrically, or more frequently asymmetrically, medifixed | 44 |
| 2 | Stems glabrous to sparsely hairy | 3 |
| Stems moderately to densely hairy
Back to 1 | 30 |
| 3 | Stipules broad (usually more than 5 mm wide), leafy, more or less triangular to ovate, often obliquely so, mostly 4–15 mm long | 4 |
| Stipules narrower (usually less than 3 mm wide), mostly triangular to triangular-acuminate, mostly 1–10 mm long, occasionally to 15 mm long
Back to 2 | 6 |
| 4 | Stems 1–4 mm diam.; leaves with 5–13 leaflets; styles tending to recurve in the upper part; pods narrow-elliptic to cylindrical, c. 3 mm diam., not inflated | Swainsona viridis |
| Stems often more than 5 mm diam., leaves with 13–19 leaflets; styles evenly incurved; pods crescent-shaped to broad-elliptic, 10–15 mm wide
Back to 3 | 5 |
| 5 | Flowers 15–20 mm long, purple; style c. 9 mm long; stipules 12–more than 15 mm long | Swainsona colutoides |
| Flowers c. 10 mm long, yellow; style c. 3 mm long; stipules 4–7 mm long
Back to 4 | Swainsona pyrophila |
| 6 | Apex of leaflets narrow and long-tapering | 7 |
| Apex of leaflets obtuse to retuse or emarginate, if acute then not long-tapering
Back to 3 | 9 |
| 7 | Leaves with 1–7 leaflets, mostly 10–40 mm long, 1–5 mm wide; calyces glabrous; wings with a large obtuse extension | Swainsona campylantha |
| Leaves with 5–13 leaflets, mostly 10–25 mm long, 1–2 mm wide; calyces pubescent; wings not as above
Back to 6 | 8 |
| 8 | Leaves with terminal leaflet distinctly longer than laterals; calyx teeth more or less equal to tube; style tip strongly curved or geniculate | Swainsona parviflora |
| Leaves with terminal leaflet not distinctly longer than laterals; calyx teeth much shorter than tube; style tip straight to curved
Back to 7 | Swainsona recta |
| 9 | Flowers mostly more than 10 mm long | 10 |
| Flowers usually less than 10 mm long
Back to 6 | 20 |
| 10 | Keel apex strongly curved upward, recurved or coiled; stipules 2–15 mm long | 11 |
| Keel tip horizontal or at most a little raised or beaked; stipules 2–5 mm long
Back to 9 | 13 |
| 11 | Keel tip strongly upcurved; style unbearded but with a ridge of hairs behind the style | Swainsona plagiotropis |
| Keel tip strongly recurved or coiled; style not as above
Back to 10 | 12 |
| 12 | Stem hairs dense or sparse, c. 0.5 mm long, curved or spreading; keel usually twisted in an incomplete circle, tip blue | Swainsona swainsonioides |
| Stem hairs sparse, minute and appressed or absent; keel spirally twisted in a complete circle, tip yellow
Back to 11 | Swainsona procumbens |
| 13 | Calyx teeth mostly 2–4 times longer than tube; bracts 12–20 mm long | Swainsona cadellii |
| Calyx teeth shorter than tube; bracts to 10 mm long
Back to 10 | 14 |
| 14 | Stems glabrous | 15 |
| Stems pubescent
Back to 13 | 17 |
| 15 | Leaves usually with 13–17 leaflets, leaflets sometimes modified or absent, sparsely pubescent on lower surface; stipe 1–2 mm long | Swainsona laxa |
| Leaves with 19–29 leaflets, not as above, mostly glabrous; stipe mostly 5–10 mm long
Back to 14 | 16 |
| 16 | Pedicels minutely pubescent, to c. 5 mm long but often much shorter; leaflets 19–25, ovate to narrow-ovate, the lower 10–20 mm long, 2–3 mm wide; wings about as long as keel | Swainsona queenslandica |
| Pedicels glabrous, usually more than 5 mm long, occasionally shorter; leaflets 21–29, narrow-obovate to elliptic, the lower 8–15 mm long, 3–5 mm wide; wings shorter than keel
Back to 15 | Swainsona galegifolia |
| 17 | Hairs on stems spreading, often fine and crisped, c. 0.5 mm long | 18 |
| Hairs on stems appressed, mostly less than 0.5 mm long
Back to 14 | 19 |
| 18 | Bracts 8–10 mm long; wings shorter than keel; pods 40–50 mm long, glabrous; lower leaflets c. 15 mm long, 5–7 mm wide | Swainsona bracteata |
| Bracts 1–2 mm long; wings scarcely or not shorter than keel; pods 25–40 mm long, glabrous or minutely pubescent; lower leaflets 10–20 mm long, 2–3 mm wide
Back to 17 | Swainsona queenslandica |
| 19 | Leaves mostly with 13–17 leaflets, leaflets sometimes modified or absent; flowers yellow, occasionally with a purple flush; style tip more or less straight | Swainsona laxa |
| Leaves with 21–24 leaflets, not as above; flowers pink to purple; style tip strongly incurved or coiled
Back to 17 | Swainsona fraseri |
| 20 | Leaves with 3–7 leaflets | 21 |
| Leaves mostly with more than 7 leaflets (occasionally less in Swainsona similis, then keel acute)
Back to 9 | 23 |
| 21 | Pods more than 15 mm long; flowers purple or yellow; style tip incurled; lateral leaflets 3–10 mm wide | Swainsona luteola |
| Pods less than 15 mm long; flowers purple; style tip inflexed, incurved or geniculate; lateral leaflets 1–5 mm wide
Back to 20 | 22 |
| 22 | Leaflets 2–15 mm long, apex obtuse to retuse; style tip straight to slightly inflexed or incurved | Swainsona oligophylla |
| Leaflets 10–25 mm long, apex acute; style tip geniculate
Back to 21 | Swainsona oroboides |
| 23 | Leaves with 21–41 leaflets; leaflets broad-cuneate to more or less circular, 1–5 mm long | Swainsona microphylla |
| Leaves with 5–25 leaflets; leaflets not as above, 1–20 mm long
Back to 20 | 24 |
| 24 | Racemes 1–4-flowered; stipules 1–2 mm long | 25 |
| Racemes mostly more than 4-flowered; stipules to 10 mm long
Back to 23 | 26 |
| 25 | Flowers 3–5 mm long, cream or yellow, more or less tinged pink; ovary and pod pubescent; lateral leaflets obovate to narrow-obovate, 1–7 mm long | Swainsona oliveri |
| Flowers 6–10 mm long, white to purple or dark red; ovary and pod glabrous; lateral leaflets ovate to elliptic to narrow-elliptic, 2–20 mm long
Back to 24 | Swainsona brachycarpa |
| 26 | Keel tip obtuse; plants prostrate to ascending or semi-erect | 27 |
| Keel tip acute; plants erect to spreading
Back to 24 | 29 |
| 27 | Leaflets 1–4 mm wide; stems glabrous or with tubercules bearing minute hairs; pods with stipe 2–3 mm long | Swainsona brachycarpa |
| Leaflets 3–10 mm wide; stems sparsely to densely pubescent, not tuberculate; pods with stipe less than 1 mm long
Back to 26 | 28 |
| 28 | Pods broad-oblong, obovoid or globose, 5–11 mm long; calyx teeth shorter than tube; leaflets 7–25, apex emarginate | Swainsona affinis |
| Pods elliptic to narrow-oblong, 20–35 mm long; calyx teeth usually more or less longer than tube; leaflets 3–17, apex obtuse to acute
Back to 27 | Swainsona luteola |
| 29 | Leaflets ovate to elliptic, laterals mostly 10–15 mm long, 2–5 mm wide; stem hairs c. 0.75 mm long, spreading and twisted or crisped | Swainsona extrajacens |
| Leaflets more or less elliptic, laterals mostly 5–10 mm long, 1–2 mm wide; stem hairs short or minute, appressed
Back to 26 | Swainsona similis |
| 30 | Hairs on stems spreading, or antrorsely divergent or curved | 31 |
| Hairs on stems mostly appressed or occasionally divergent, the ends sometimes raised
Back to 2 | 39 |
| 31 | Stems densely hairy, woolly with emergent, straighter hairs; pods globose and woolly | Swainsona burkittii |
| Stem indumentum not as above; pods if globose not woolly
Back to 30 | 32 |
| 32 | Hairs on stems 1–2 mm long; flowers 5–6 cm long, red or occasionally white or parti-coloured, base of standard with a conspicuous black, glossy mound | Swainsona formosa |
| Hairs on stems mostly less than 1 mm long; flowers ± 2.5 cm long, usually purple or pink, sometimes yellow, orange or white; standard not as above
Back to 31 | 33 |
| 33 | Leaves with 21–41 leaflets; leaflets broad-cuneate to more or less circular, 1–5 mm long | Swainsona microphylla |
| Leaves with 5–25 leaflets; leaflets obovate to elliptic or narrow-lanceolate, mostly 5–15 mm long
Back to 32 | 34 |
| 34 | Keel tip conspicuously twisted; hairs on stems spreading or antrorsely curved | Swainsona swainsonioides |
| Keel tip not as above; hairs on stems spreading or antrorsely divergent
Back to 33 | 35 |
| 35 | Leaves with 5–15 leaflets; flowers 5–10 mm long, bracts 1–4 mm long | 36 |
| Leaves with 15–25 leaflets; flowers 12–25 mm long, bracts 5–10 mm long
Back to 34 | 38 |
| 36 | Leaflets 5–10 mm wide; keel usually greenish yellow | Swainsona flavicarinata |
| Leaflets 1–3 mm wide; keel tip purple
Back to 35 | 37 |
| 37 | Leaflets mostly opposite, the terminal somewhat longer than laterals; style with the translucent tissue not broad in the upper part; calyx hairs mostly dark brown to black. | Swainsona behriana |
| Leaflets including terminal often irregular; style with the translucent tissue wing-like and broad in the upper part; calyx hairs dark, light or mixed.
Back to 36 | Swainsona reticulata |
| 38 | Calyces white-woolly, teeth much shorter than tube; stipules 4–10 mm long | Swainsona greyana |
| Calyces pubescent with dense to sparse crisped hairs, teeth shorter than to more or less equal to tube; stipules usually 2–5 mm long
Back to 35 | Swainsona bracteata |
| 39 | Pods 20–35 mm long, distinctly tapered at apex; leaflets 3–10 mm wide; flowers purple or yellow | Swainsona luteola |
| Pods 5–15 mm long, not distinctly tapered at apex; leaflets 1–5 mm wide; flowers purple, pink or white
Back to 30 | 40 |
| 40 | Leaves with 3–7 leaflets; calyx teeth longer than tube; racemes 3–7-flowered; ovaries and pods pubescent | 41 |
| Leaves with more than 10 leaflets; calyx teeth equal to or shorter than tube; racemes 3–25-flowered; ovaries and pods more or less glabrous
Back to 39 | 42 |
| 41 | Leaflets 2–15 mm long, apex obtuse to retuse; style tip straight to slightly inflexed or incurved | Swainsona oligophylla |
| Leaflets 10–25 mm long, apex acute; style tip geniculate
Back to 40 | Swainsona oroboides |
| 42 | Leaves with 21–41 leaflets; leaflets broad-cuneate to more or less circular, 1–5 mm long; style tip truncate | Swainsona microphylla |
| Leaves with 7–25 leaflets; leaflets oblong, narrow-obovate or elliptic, 2–15 mm long; style tip geniculate or obliquely narrowed
Back to 40 | 43 |
| 43 | Leaflets to 3 mm wide; flowers 4–7 mm long; style tip geniculate | Swainsona monticola |
| Leaflets 3–8 mm wide; flowers 6–10 mm long; style tip obliquely narrowed
Back to 42 | Swainsona affinis |
| 44 | Flowers usually orange-red or brown, rarely yellow or purple; stipules broad, with broad lateral teeth | Swainsona stipularis |
| Flowers purple or occasionally pink; stipules triangular to acuminate-triangular, usually without obvious teeth
Back to 1 | 45 |
| 45 | Leaflets with a circular, yellowish gland at apex | Swainsona adenophylla |
| Leaflets without an apical gland
Back to 44 | 46 |
| 46 | Stem hairs mostly less than or equal to 0.5 mm long | 47 |
| Hairs on stems greater than 0.5 mm long
Back to 45 | 49 |
| 47 | Leaflets obovate, mostly 2–15 mm long; calyx teeth long-attenuate, 3–4 times as long as tube | Swainsona oligophylla |
| Leaflets linear, linear-lanceolate to elliptic, mostly 5–30 mm long; calyx teeth equal to or shorter than tube
Back to 46 | 48 |
| 48 | Flowers not twisted at the base of the calyx; apex of leaflets acute to sinuate or emarginate; racemes 3–20-flowered | Swainsona purpurea |
| Flowers twisted at the base of the calyx; apex of leaflets mostly narrow-acute; racemes 3–11-flowered
Back to 47 | Swainsona murrayana |
| 49 | Flowers 10–15 mm long, keel conspicuously longer than wings; hairs on stems mostly 1–1.5 mm long | Swainsona phacoides |
| Flowers 7–11 mm long, keel not as above; hairs on stems mostly 0.5–1 mm long
Back to 46 | 50 |
| 50 | Prostrate or low-growing, to c. 10 cm high; style tip truncate or rounded and geniculate; pods obovate to narrow-obovate, 10–17 mm long | Swainsona sericea |
| Erect or ascending, to 50 cm high; style tip rounded and minutely incurved; pods mostly elliptic, 15–25 mm long
Back to 49 | Swainsona fissimontana |
