Selago linearis is a single-stemmed, but branched shrub growing erect stems to 50 cm, not resprouting after fire. 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 distribution is in the east of the Western Cape, from the Little Karoo and coastally to the west of the Eastern Cape as far as Gqeberha.
It grows in sandy or loamy soils on fynbos and renosterveld slopes, often near watercourses. The species is not considered threatened in habitat early in the twenty first century (Vlok and Schutte-Vlok, 2010; iSpot; http://redlist.sanbi.org).