Psoralea karooensis C. H. Stirt., Muasya & Vlok

Habiterect, willowy, flexuose branched shrub to 3 m tall, reseeder but coppices regularly once established. Stems 1(2), brownish-grey with scattered white lenticels, weakly fissured, bare of leaves except on the seasonal shoots which arise in a characteristic burst-branching; shoots coppice seasonally on old stems, leafy along their entire length, glaucous green with a whitish bloom, glabrous, with small raised crateriform glands. Leaves 1-foliolate, petiolate, stipulate, glandular, glabrous. Leaf size variable, being larger on water shoots from the rootstock (20–23 mm long, 2–3 mm wide), becoming smaller up the flowering shoots, dull glaucous green; apex rounded to acute; base cuneate; tip arching; petiole 1–2 mm long. Stipules 1–2 mm long, fused at base, rigid, triangular, semi-patent, 1-veined, rapidly senescent on flowering shoots. Flowers 10.0–12.5 mm long, greenish cream, borne in most axils of the upper half of the seasonal shoots, 1–3 per axil; pedicels 2 mm long. Peduncles 10–12 mm long, purple-tinged, terminated by a small tri-toothed cupulum; cupulum teeth equal, broadly triangular, acute, green, <1.0mm long. Calyx 5 mm long, pale green, sometimes flushed with purple, glabrous; teeth triangular, all 2 mm long, carinal tooth broadest, blunt, weakly ribbed, glandular; tube longer than the teeth, accrescent in fruit, persisting after fruits and seeds are shed. Standard broadly elliptic, 10 mm long, 10–12 mm wide; claw 2 mm long, almost tubular; cream, nectar flash purple rising from above the strongly developed auricles to the apex; inner face of the standard greenish, veins purple; apex emarginate but standard not fully reflexed. Wing petals 10–11 mm long, 4 mm wide; claw 2.5 mm long; locked into keel fold but not fused, slightly longer than the keel, petal sculpturing present, upper basal, comprised of 4–5 transcostal parallel lamellae. Keel petals 10 mm long, 3 mm wide; claw 5 mm long; apex deep purple. Androecium 9 mm long; tenth stamen free; sheath split adaxially, fenestrate. Pistil 9 mm long; ovary 1.5 mm long, sessile, glabrous, thickened before point of flexure, height of curvature 3 mm, erect, penicillate. Fruits ovate, indehiscent, wall scarious, 3.8–4.1 mm long and 2.2–2.5 mm wide at mid length. Seed 3.5–4.0 mm long and 2.1–2.2 mm wide at mid length, dark olive green, smooth, aril present and light olive green.

Psoralea karooensis grows in the Klein Karoo mountains, between 1000–1200 m. It is restricted to the Witteberg quartzite fynbos vegetation, between the Witteberg and Anysberg Mountains, and occurs mainly in gulleys and along the banks of dry river beds (Plate 2).