Small tree or shrub, winter–deciduous, not spinescent, 1—several–stemmed at base, in range to 600 cm tall; shoots with only cauline leaves, short–strigose, lacking glandular hairs.
Stems initially ridged aging with periderm and cylindric, young twigs with prominent projecting leaf bases.
Leaves helically alternate, odd–1–pinnately compound with 9—17 leaflets (strongly folded in bud, conduplicate), leaflets mostly paired and opposite r subopposite, petiolate with pulvinus, with stipules; stipules 2, attached to lower petiole, linear, to 3.5 mm long, short–hairy, early–deciduous; petiole 18—32 mm long, pulvinus 1.5—2.5 mm long, short–hairy, with 2 pits near base where stipules formerly attached, above pulvinus channeled; rachis channeled like petiole, to 90 mm long, short–hairy on upper side; stipel at base of petiolule on ridge, ascending, acuminate, 0.4—1.5 mm long, blackish at tip, short hairs curved upward; petiolule = a wrinkled pulvinus 2—2.5 mm long, yellow–green; blades of leaflets ± symmetric, ovate to elliptic (terminal leaflet sometimes obovate), 7—30 × (< 5—)6—14 mm, tapered at base, entire, acute to obtuse at tip appearing minutely notched with a backward–curved to lower surface, pinnately veined with midrib raised on lower surface, upper surface initially short–hairy aging glabrescent except with hairs along midrib, lower surface short–strigose with upward–pointing hairs and paler than upper surface.
Inflorescence raceme, axillary from a low node on new spring shoot, pendent below foliage, mostly 15+–flowered, bracteate, short–strigose; peduncle cylindric, to 23 mm long not increasing in fruit; rachis cylindric with projecting bractlet bases, after flowering < 100 mm long; bractlet subtending pedicel linear, 0.9—1.5 mm long, early–deciduous (in early flower bud); pedicel cylindric, to 5.5 mm long increasing 2× in fruit.
Flower bisexual, bilateral, pealike (papilionaceous), ca. 11 mm across, nectary nectar–producing receptacle below ovary; calyx inconspicuously lobed, bell–shaped and somewhat boxy, 3—3.5 × 4 mm, green or blushed purplish, short–strigose with upward–pointing hairs; petals 5, free, clawed; banner claw flat, ca. 3 × 1 mm, white, limb bent backward from claw and widely spreading, roundish, 10.5—11.5 mm, white or somewhat pale pink with bright yellow central blotch with nectar lines radiating outward, having a shallow groove along midline, slightly notched at tip; wings 2, projecting forward ⊥ banner limb and parallel with keel, claw linear, 3.5—4 mm long, rose–lavender, limb ovate, 10.5—11.5 × 6—6.5 mm, < wings, light purple to darker at tip, with a basal lobe on upper edge white at tip, obtuse at tip, midvein below midline and curved to tip; keel of 2 separate petals, claw linear, ± 4 mm long, limbs overlapping in bud and at anthesis, cupped–triangular, ca. 9 × 6.5—7 mm, light purple at base to dark purple at tip; stamens 10, diadelphous (9 fused + 1 free), concealed within keel; filament sheet only 1.5 mm long, free portions ca. 10 mm long and curved upward from midpoint and subequal, of free stamen ca. 9 mm long, white, glabrous; anthers dorsifixed, dithecal, ± 0.9 mm long, yellow–orange, longitudinally dehiscent; pistil 1, stalked (stipe), stalk green and glabrous; ovary superior, cylindric, ca. 5.5 × 1 mm hidden by a dense cover of white hairs, 1–chambered with ca. 12 ovules attached to upper side; style tapered and curved gradually upward, ca. 5 mm long, light green at base to pale green at top, with a minute terminal stigma at the level of the longer stamens, stigma papillate and lacking short hairs.
Fruit pod (legume), stalked, pendent, indehiscent, 1—4–seeded, conspicuously and narrowly constricted between seeds like a bead necklace, 33—70(—150) mm long (including beak, style) rarely not constricted by with bulging seeds, exocarp leathery, black and wrinkled, pulp (mesocarp) fleshy and sticky, segments subspheroid, 9—11.5 × 6.5—8 mm, connecting by slender cylinder of tissues; pedicel to 11 mm long, short–tomentose.
Seed lens–shaped ovoid to ellipsoid, 5—5.8 × 3.3—3.7 × 2 mm, dull dark brown to blackish, with hard seed coat, often with a deeply indented hilum.
A. C. Gibson