The markedly succulent leaves of Senecio barbertonicus are cylindrical or almost so, but for the flattish upper surfaces as seen as in the photo. The leaves are sessile, i.e. stalkless or nearly so. Slightly incurving, the leaves are 5,5 cm long and about 5 mm in diameter. There are a few longitudinal dark green lines (veins) seen on the leaf surfaces in picture. Leaf tips taper to acute points; in the photo many of them are yellowish.
The leaves are bunched densely together and ascending at stem tips. They spread in the next sections below that while further down they sag, just above the pale grey, bare stems where leaves of a few seasons ago have disappeared (Germishuizen and Fabian, 1982; Van Wyk and Malan, 1997; www.plantzafrica.com).