Psoralea speciosa Eckl. & Zeyh.

A small to large, robust, colonial, reseeding shrub up to 2.5 m tall. Stems erect, 1-3, branching at or near the base, stiff and arching, blackish brown, pubescent; branches short, stiffly erect, rigid. Seasonal shoots glabrous, dark green. Leaves 5-foliolate, distributed along the branches but on older plants occur only at the tips, rounded, petiolate, papillose on the margin, glabrous, channelled on both surfaces; leaflets 10-22 x 0.3-0.4 mm, but longer (18-22 mm) at base of seasonal shoots, linear lanceolate, terminal leaflet shortest, basal pair longest, three uppermost digitately inserted, rarely pinnately; petioles 2-4 mm long, shorter than terminal leaflets; rachis 3-7 mm long; stipules 3 x 1.5 mm caducous, triangular, puberulent, glandular. Inflorescences axillary, borne vertically on short vernal shoots off horizontal branches along the length of seasonal shoots but without leafy extension, pseudo-capitate, lax, pedunculate, 4-5 flowers per axil, pedicellate; peduncles stout and rigid, 1-3 mm long, shorter than the subtending leaf; cupulum trilobed, 2-3 mm long, glabrous, one of the lobes scarcely developed, triangular, inner bracts absent; pedicels 1-2 mm long. Flowers 17-18 mm long, deep blue or indigo-blue, each flower subtended by a pair of small cucullate bracts. Calyx 10-12 mm long, tube 5-8 x 6 mm, glabrous but fringed with dark hairs, nigro-punctate, fleshy, yellowish, accrescent, persistent after seed shed, densely glandular; lobes unequally developed, shorter than the tube, broadly triangular, carinal much broader, vexillar lobes fused 2 mm above the tube, incurving, acuminate, inner face covered with soft white hairs. Standard petal 14-15 x 14-16 mm, very broadly ovate, deep blue or indigo-blue with large white M-shaped nectar guide, central purple flash absent, veins darker than blade, appendages present; claw 2-4 mm long. Wing petals 12-13 x 4-5 mm, same colour as standard, completely covering the keel, sculpturing present, upper and lower basal comprised of 2-4 arching lamellae, pocket well developed, auricle swollen, folded along the mid-line; claw 4-5 mm long. Keel 11 x 4 mm, acute at the apex; claw 5-6 mm long. Androecium 12 mm long, tenth stamen lightly attached, fenestrate. Pistil 11 mm long, ovary 1.5-2 mm long, glandular, style straight 6 mm long, then curved, entasis well developed at mid-point, height of curvature 5 mm long, stigma capitate, penicillate. Fruits 5-6 x 2.5-3.0 mm, oblong. Seeds 3-5 x 2.5 mm, dark brown to black.