Rupestris means growing on rocks, a very apt name for a species which is often common on dry stony slopes.
The plants occur widespread from near Vanrhynsdorp to the Cape Peninsula and the Eastern Cape. They form shrublets to 60 cm tall, usually with many, somewhat brittle stems.
The branches are erect or spreading, sometimes creeping, with egg- to lance- shaped leaves often with a waxy bloom. There is a great variability in the colour, size and shape of the leaves and also in the degree to which they are fused at the base.
The flowers appear over quite a long period: June-October.