[1] Specimen of this small shrublet were first collected by the famous South African botanist Harry Bolus in 1904, high on the northern slopes of the Swartberg Pass.

In 1986, Charles Stirton considered it sufficiently different from other Otholobium species, in particular O. sericeum, to distinguish and name it O. swartbergense.

At its tip it carries three, flat, elliptical leaflets of 15–22 mm (0.59–0.87 in) long and about 6–8 mm (0.24–0.31 in) wide, with an blunt base, an entire margin and a tip that ends abruptly in a small, sharp, recurved point as a continuation of the midrib.

[1] The flowers grow in roundish heads of 6-15 together on peduncles of 5–20 cm (2.0–7.9 in) long that emerge from the axils of the leaves.

Each head consist of 2-5 triplets of flowers, the lowest of which is subtended by a semi-circular, hairy bract that divides in 2 or 3 teeth.

Each individual flower sits on a pedicel of 1.5–2.0 mm (0.059–0.079 in) long and is subtended by a very narrow bract.

As in all Faboideae, the corolla is zygomorphic, forms a specialized structure and consists of 5 free petals.

[1] Otholobium swartbergense is considered a near-threatened species because it is known from six locations only and may suffer from competition by invasive plants.