Indigofera nigromontana, in Afrikaans the doringertjie (thorn pea), is a long-living woody shrub that grows to 1,5 m, occasionally taller. It sprouts after fire or heavy browsing. The branched stems are grey-brown to pale grey, even whitish. Bark on older branches is shallowly fissured. The plant is sometimes sparsely spiny, while small side-branches taper and dry out also to appear spine-like. This earned it the name of thorn pea, the flower shape resembling that of the garden pea.
The specific name, nigromontana meaning black mountain links the plant to the Swartberge. The plant occurs in a variety of scrub vegetations, renosterveld and fynbos, from Namaqualand, the Karoo and Little Karoo to Grahamstown and Lesotho. It grows on mountain slopes and by riverbanks in shale and various soils, often in semi-arid conditions, being drought-adapted. This plant was photographed at the end of autumn in the Rooiberg. It is the grey-leaved or silvery form (Vlok and Schutte-Vlok, 2010; JSTOR; iSpot; www.plantzafrica.com).