Leaves alternate, simple, linear, terete, or ± trigonous, with a groove along the upper surface, [rarely almost flat with inrolled margins]; stipules occasionally conspicuous but usually minute or absent.
Inflorescences racemose, umbellate or capitate, axillary or terminal; bracts small, caducous or persistent; bracteoles small, on pedicel often distant from the calyx, caducous or persistent. Calyx teeth short or as long as the tube, the 2 upper teeth ± united into a lip, apices parallel or divergent. Petals yellow or yellow and red to deep orange-red, clawed; standard broader than long; the wings narrow, auriculate at base of lower margin; keel shorter than or equal to wings, straight or scarcely incurved. Stamens free, often attached to a ring at base of calyx tube. Ovary shortly stipitate, pubescent; style erect, thick, hooked below the apex with a truncate or thick stigma; ovules 2 on short funicles.
Pods nearly sessile, ovoid or globose, turgid; seeds smooth or ornamented, with an aril.
| | Key to the species | |
| 1 | Leaves distinctly spirally twisted | 2 |
| Leaves not twisted or rarely slightly so | 9 |
| 2 | Inflorescences terminal and/or in the upper axils, racemose with 1 to several flowers, often pedunculate | 3 |
| Inflorescences axillary, consistently 2-flowered, ± sessile
Back to 1 | 8 |
| 3 | Leaves coverd with dense rather stiff hairs or, if almost glabrous, mature leaves with a few stiff hairs only near apex; calyx glabrous externally or with a sparse to moderate cover of stiff hairs, margin ciliate or not | 4 |
| Leaves glabrous; calyx glabrous externally, margin usually shortly ciliate with weak hairs
Back to 2 | 5 |
| 4 | Spreading (rarely prostrate), diffuse to erect shrubs to 1.5 m high; leaves covered in hairs; calyx usually with stiff hairs externally; widespread along the dividing range | Dillwynia phylicoides |
| Prostrate shrubs to 0.1 m high; mature leaves with stiff hiars only at the apex (young leaves with scattered hairs); calyx glabrous externally; Ebor district (NT)
Back to 3 | Dillwynia sp. Ebor (P.C.Jobson 5318 & S.A.Mills) |
| 5 | Erect to diffuse shrubs 0.5–2.5 m high | 6 |
| Weak ascending shrubs <0.5 m high
Back to 3 | 7 |
| 6 | Leaves mostly >5 mm long; widespread, north from the Budawang Ra. (NC, CC, SC, CT, NWS) | Dillwynia retorta |
| Leaves mostly 1–5 mm long; restricted to the Cumberland Plain, and to Douglas Park (CC)
Back to 5 | Dillwynia parvifolia |
| 7 | Peduncles 5–15 mm long; widespread, grows in heaths and open woodlands (NC, CC, CT, ST) | Dillwynia trichopoda |
| Peduncles 11–28 mm long; restricted to alpine swamp margins (ST)
Back to 5 | Dillwynia palustris |
| 8 | Leaves flattened or trigonous in section, branchlets with long spreading to antrorse hairs; on coastal sand and sandstone, north from Ulladulla (NC, CC, SC) | Dillwynia floribunda |
| Leaves terete or almost so, branchlets with short appressed hairs; on rocky sandstone ridges from Port Jackson to near Rylstone (CC, CT)
Back to 2 | Dillwynia elegans |
| 9 | Calyx tapering gradually towards the base; petals not persistent in fruit | 10 |
| Calyx abruptly narrowed at the base; pods surrounded by the persistent remains of the petals
Back to 1 | 20 |
| 10 | Calyx tube hairy | 11 |
| Calyx tube glabrous
Back to 9 | 13 |
| 11 | Inflorescences with peduncles 0.5 mm or longer | 12 |
| Inflorescences with ± sessile flowers or peduncles <0.5 mm long
Back to 10 | Dillwynia sericea |
| 12 | Lateral stems and branchlets spinescent | Dillwynia ramosissima |
| Lateral stems not spinescent
Back to 11 | Dillwynia hispida |
| 13 | Prominent decurrent leaf bases absent | 14 |
| Prominent decurrent leaf bases present
Back to 10 | 18 |
| 14 | Leaves with apex strongly hooked (as opposed to apex recurved) | 17 |
| Leaves with apex ± straight (sometimes recurved but not strongly hooked)
Back to 13 | 16 |
| 15 | Inflorescences 1–4-flowered, corymbose on peduncles >3 mm long | Dillwynia glaberrima |
| Inflorescences 1–2-flowered, at the end of lateral branches on peduncles <3 mm long
Back to | Dillwynia tenuifolia |
| 16 | Plants prostrate | Dillwynia prostrata |
| Plants erect
Back to 14 | 17 |
| 17 | Inflorescences 2-flowered; on rocky sandstone ridges from Port Jackson to near Rylstone (CC, CT) | Dillwynia elegans |
| Inflorescences 1-flowered; known from the Windellama, Michelago and Numeralla areas (ST)
Back to 16 | Dillwynia glaucula |
| 18 | Stipules present; inflorescences 2-flowered | 19 |
| Stipules absent; inflorescences 1-flowered
Back to 13 | Dillwynia sp. Barren Grounds (Chadwick s.n. NSW 39509) |
| 19 | Stipules 0.5–1.5 mm long; grows in swampy heaths | Dillwynia stipulifera |
| Stipules 0.1–0.5 mm long; grows in heath near escarpments
Back to 18 | Dillwynia crispii |
| 20 | Leaf apex either obtuse or if acute without an obvious sharp or pungent point | 21 |
| Leaves with an obvious sharp to pungent point
Back to 9 | 23 |
| 21 | Inflorescences sessile, dense, terminal heads | Dillwynia brunioides |
| Inflorescences racemose, corymbose or single-flowered, terminal or axillary, never forming sessile, terminal heads
Back to 20 | 22 |
| 22 | Flowers pedunculate; bracteoles narrow-lanceolate, caducous; from between Deniliquin and Moama (SWP) | Dillwynia cinerascens |
| Flowers sessile; bracteoles broad-lanceolate to ovate, persistent; known from near Bathurst, Yass, Canberra and Tarcutta (CT, ST, SWS)
Back to 21 | Dillwynia sp. Yetholme (P.C.Jobson 5080) |
| 23 | Leaves terminated by a distinctly pungent point 1–1.5 mm long | 24 |
| Leaves terminated by a sharp but not pungent point 0.2–0.5 mm long
Back to 20 | 25 |
| 24 | Leaves sessile | Dillwynia juniperina |
| Leaves with short yellowish petiole, 0.4–1.2 mm long
Back to 23 | Dillwynia sieberi |
| 25 | No obvious leaf base scars; standard 7–9 mm long; from the Goulburn R. to Bargo (CC, CT, CWS) | Dillwynia acicularis |
| Obvious leaf base scars present; standard 9–12 mm long; Gibraltar Ra. (NT)
Back to 23 | Dillwynia rupestris |
