Dunn (1912a) recognised the distinctiveness of the Australasian species when he placed all three in his MillettiaSect.Austromillettia Dunn. He noted the single flowers as opposed to flowers in pairs (sometimes more than two branching from the same place on the inflorescence axis in other Millettia spp.), and the terete woody nature of the pods (Dunn 1912a: 135, 138, 140).

Austrocallerya comprises three Australasian species with glabrous or finely pubescent young leaves and stems (vs. these densely brown tomentose in Padbruggea, see Table 4 and Fig. 6). The robust paniculate inflorescences are more erect than those in Padbruggea and the flowers have very broad standard petals with a recessed dividing midline. Either side of the midline is an arch callosity which forms a short crescent arching over the staminal sheath (vs. papillate or ridge callosities in Padbruggea). The pods are fusiform (vs. obovoid or compressed-cuboid in Padbruggea), torulose and with either longitudinal striations and furrows (A.megasperma), or with irregular fine striations (A.australis) or smooth (A.pilipes), the surface in all cases being densely velutinous or pubescent. The pods of Austrocallerya can be distinguished from those of Padbruggea, which are also densely velutinous, by their outline. Padbruggea pods are either obovoid (in P.filipes) or oblong with a prominent dorsal midline flanked by two large flanges meeting at the apex (P.dasyphylla). The pods in Austrocallerya are 30–52 mm wide (vs. 40–110 mm wide in Padbruggea). The 2–10 seeds in Austrocallerya are oblong, ellipsoid or globose, frequently with one side compressed within the pod (vs. 1–2 elliptic-ovoid or prolate-spheroid seeds which may also be laterally compressed in Padbruggea). In Austrocallerya the strap-shaped hila are 16–30 × 2–4 mm, (vs 16–40 × 5–10 mm in Padbruggea). Fig. 6.

Austrocalleryaaustralis (Endl.) J.Compton & Schrire ≡ Pterocarpusaustralis Endl.

Three species of robust, twining woody vines scrambling from 2–20 m in height. Stems grey, tan or reddish brown, terete, mature stems and branches exhibiting a flaky peeling bark, young growth sericeous-pubescent becoming glabrous. Stipules 1.5–6 mm long, deltoid or filiform, sericeous, caducous (persistent in A.megasperma). Stipels 1–4 mm long, filiform, sericeous, persistent or caducous (absent in A.pilipes). Leaves evergreen, coriaceous and nitid when mature, imparipinnate with 5–19 leaflets, rachis 7–25 cm long, pubescent becoming glabrous. Leaflets 3–14 × 1–7 cm, elliptic, narrowly oblong or obovate, upper surface glabrous, lower surface with scattered hairs especially along veins, apex obtuse, retuse, emarginate, acute, acuminate or caudate, margins entire, base truncate, obtuse or cuneate. Inflorescence a robust many-flowered terminal panicle 6–40 cm long, sericeous or pubescent. Flowers 11–16 mm long, emerging from September to December (in A.australis from December to April but in New Guinea from June to October). Floral bracts 2–7 mm long, (8–15 mm in A.pilipes), white, green or pink, sericeous, cupuliform or linear or ovate to narrowly ovate, caducous. Bracteoles 1–7 mm, at top of pedicel, linear, sericeous, acuminate, caducous. Pedicels 3–21 mm long, pinkish, sericeous or pubescent. Calyx 3–7 × 4–10 mm, campanulate, yellowish or purple, glabrous internally, sparsely pubescent or sericeous externally, five lobed, upper teeth acute, 4–5 mm long, lower teeth 3–5 mm long, acuminate. Standard 12–22 × 11–18 mm, orbicular or broadly elliptic, whitish, reddish-purple, mauve, lilac, pink or purple, deflexed backwards near the base, apex with a short mucro, lamina veined, nectar guide yellow, greenish yellow or lime green, radiating up the centre of the lamina from the base, back of standard pubescent, callosities arched over the staminal sheath and divided centrally by a linear sinus, each half forming an arch. Wing petals 11–14 × 5–6 mm, purple or maroon, equalling keel in length, glabrous, each semi-pandurate with basal claws 2–3 mm long. Keel petals11–14 × 4–6 mm, dark reddish, purple or maroon (white with purple apices in A.megasperma), glabrous or upper margin ciliate at base (A.australis), petals united into a semi-pandurate cup, apex obtuse. Wings and keel petals spreading after anthesis. Stamens diadelphous, nine fused together, the vexillary one free, all curved upwards at apex, glabrous. Ovary sericeous, style 3–5 mm long, curved upwards at apex, stigma punctate. Pods 7–23 × 3–5.2 cm, fusiform, inflated, torulose, tardily dehiscent, exocarp finely ridged, longitudinally striate (smooth in A.pilipes), surface velutinous, endocarp chartaceous, the seeds in hollow cavities, subseptate. Seeds (1 –) 2–6, ellipsoid, broadly ovoid to squarish, smooth, brown or orange-brown 12–43 × 12–42 × 12–41 mm, sometimes compressed laterally inside the pod, hilum 16–30 mm x 2–4 mm, strap-shaped. Fig. 6.

Australia (New South Wales, Queensland); Papua New Guinea (Bougainville Island, New Britain Island); New Caledonia; Cook Islands.

In rainforest or in dry forest from sea level to 1600 m, climbing up trees and over shrubs.

The generic name reflects the southern hemisphere distribution of the genus, austro - “australis” = south (Latin) and “callerya” a reference to their former generic placement and affinity.