Psoralea nitens is an upright, profusely branching, somewhat cylindrical shrub of up to high. From the ground emerge one to many shiny silky, softly hairy stems with the
nodes close to each other. The
alternate leaves are set at an upward angle, have at their base two asymmetrical, oval lance-shaped to triangular, softly hairy, papery
stipules with dot-like glands and a striped appearance due to parallel veins, that clasp the stem and are long and about 3 mm wide. The
petiole is long, and remains after the leaflets have been shed. The 3 leaflets each sit at the tip of a
petiolule of about long. The two lateral leaflets are asymmetrical, slightly sickle-shaped, about two thirds of the length of the middle leaflet at , exceptionally up to long and , exceptially up to wide. The leaflets are narrowly inverted egg-shaped to inverted egg-shaped, have a wedge-shaped base, a margin with very fine rounded teeth, the midrib extending beyond the leaflet blade into a hooked point. Plants in the Hottentots Holland Mountains have relatively wide leaflets. The leaf surface is shiny, and has many, both sunken and raised, somewhat translucent
glands that turn reddish brown or blackish when dry. Young leaflets are hairless except for prominent adpressed silky hairs along the midrib and margins. The inflorescences consist of 3 flowers on an
inflorescence stalk of long that emerges from the axils of the leaves on the short shoots. Subtending each flower cluster is an oval bract with dot-like glands and black hairs that is about long and wide. Individual flowers are long. The
calyx is hairless except for black hairs pressed along the veins and margins. The calyx is merged at it base into a funnel-shaped tube of about long that extends into unequal lobes of long. The tooth subtending the keel is wide, which is 3–4 times wider than the other teeth. As in most
Faboideae, the corolla is
zygomorphic, forms a
specialized structure and consists of 5 free petals. The upper petal, called the banner or standard is inverted egg-shaped or elliptic, long and wide, mauve with purple veins and a large purple
nectar guide extending from the claw. The wider part at the top called the
blade is slightly indented at the tip and extends to 2 very shallow lobes (or
auricles) facing the base, and extending down between the lobes into a narrow part called
claw of about long. The two side petals called wings have blades of about long and wide, which is twice longer than the keel blades that they enclose, and the claws at their base are about long. The wing blades are adorned with up to 20 ridges and swollen tips. The 2 keel petals stick together along their base and are long and about wide, with a long claw at its base and a slightly beaked tip. The keel envelops a hollow, open tube of long, made up of 9 merged
filaments and 1
stamen that is only fused in the lower third, all topped by equally long anthers of long. Largely hidden in this
androecium is a long
pistil, including at its base the ovary of about long that is adorned with sparse glands. At the tip the ovary extends into a forward sloping style that is thickened at the place where it curves upwards about 1.5 mm from its end. The pistil it topped by a small
stigma with brush-like hairs. This
gynoecium develop into a hairless
pod of about long and wide, with a papery skin supported by netted veining. The only seed in each pod is chestnut brown in colour and long, wide with the attachment scar (or
hilum) mid-length.
Differences with related species Psoralea nitens differs from
P. mundiana by the characteristically numerous and variously-sized leaf glands, drying black (not sparse, more or less evenly sized glands that dry reddish orange), narrower, 3–3.5 (–11) mm wide leaflets (not 7–11 mm wide), mauve or bluish purple standard with deep purple nectar guide (not white standard with green nectar guide), the lowest tooth of the calyx with black hairs and 3 times wider than the other teeth (not white-haired and twice as wide other), and the wing petals twice as long as the keel petals (not wing petals only one third longer than keel petals). == Conservation, distribution and ecology ==