Pteronia viscosa, in Afrikaans the gombos (gum bush), is a shrublet with rigid, spreading branches. It grows 50 cm tall.
The shrub branches much, the stems growing woody and gnarled with rough grey and whitish bark. Young stems are reddish.
The leaves are green, small and thick, opposite, sometimes with small rigid hairs on the margins. The leaf shape is oblong to elliptic with a sharp tip and a central longitudinal groove along the surface. Leaves drop off in dry seasons so that stressed plants show only the younger ones near branchlet ends.
Gombos is found in the Western Cape in the Karoo, the Little Karoo, in the south of the Northern Cape Karoo to Calvinia and the west of the Eastern Cape.
The habitat is quartzite outcrops where the soil is often clayey. The species is not considered threatened in habitat early in the twenty first century.
Some say the plant is much browsed by livestock and game, while other records assert that browsing happens only in hard times. However this may be, the plant is more abundant in well managed than overgrazed veld, pointing to the former (Vlok and Schutte-Vlok, 2015; Shearing and Van Heerden, 2008; JSTOR; http://redlist.sanbi.org).