Psoralea filifolia Eckl. & Zeyh.

Large shrub, 3.5-4.0 m tall, reseeder, forms dense clumps. Stems single, woody throughout, terete, not furrowed, greyish, with white lenticels; branches stiff, emerging at height of about 1.5 m, several branches produced per node, giving the plant a somewhat ruffled or scruffy appearance. Seasonal shoots dark green, smooth, 1-3-foliolate; leaves 15-20 mm long, hemispherical in cross-section with a straight, sharp and hard mucro at the apex; leaflet glands in dry state visible with a x10 hand lens, reddish black, impressed on surface, denser on upper surface; petioles 2 mm long. Scales 3.5-4.0 x 1.0 mm, persistent, glabrescent, not tightly congested. Inflorescences borne in most axils of seasonal shoots, pseudo-spicate, congested (up to 40 flowers per shoot), with 1-3 flowers per axil; pedicels below cupulum 4 mm long, stout and rigid; cupulum bilobed with one of the vexillar lobes variously bilabiate; pedicel above cupulum 4 mm long; cupulum lobes equally developed, narrowly triangular, hairy on lobe margins and along adaxial midrib; cupulum glands dense, conspicuous, reddish orange. Flowers 16-20 mm long, mauve, maturing sequentially. Calyx tube 3-4 mm long, completely glabrous on the outside, but inner face of calyx lobes sparsely covered in small black stubby hairs; calyx lobes subequal, same length as the calyx tube; lateral and vexillar calyx lobes acute, straight, lanceolate; lower lobe 4 mm long, 2 mm wide, acute, broader than the other four lobes and slightly longer; calyx shorter than corolla; glands dense, small, constant in size and equally distributed across the calyx tube and lobes. Standard petal 8-9 x 10-12 mm, broadly ovate; claw 5 mm long, narrow; apex emarginate; auricles well developed. Wing petals 12-14 x 4 mm, cultrate with a strong fold along the midline, up-curving, fused to but longer than keel; auricles present, swollen; claw 4-5 mm long. Keel 10-11 x 4-5 mm; claw 6 mm long; apex rounded. Androecium 9 mm long, fenestrate. Pistil 9 mm long, pedicellate; ovary 1 mm long; style filiform, 7 mm to point of flexure, swollen before point of flexure, length of curvature 3 mm; stigma penicillate. Fruits 5 x 3 mm, papery, strongly reticulate, black. Seeds 2 x 1 mm, black; hilum sub-central, aril well-developed, 1 mm long.