Selago linearis is a branched shrub growing erect stems to 50 cm. The ascending, narrowly obovate or oblong leaves become about 1 cm long and 1 mm wide.
The mauve flowers grow at branch tips in dense, shallowly rounded heads. The funnel-shaped corolla is five-lobed and two-lipped upon a cup-shaped calyx. The four stamens protrude above the flower mouth, showing their yellow anthers. Flowering happens in spring and summer.
The plant does not sprout after fire. It grows in sandy or loamy soils on fynbos and renosterveld slopes, often near watercourses. The distribution is from the Little Karoo eastwards into the Eastern Cape (Vlok and Schutte-Vlok, 2010; iSpot).