The leathery leaves of Lasiosiphon deserticola cluster stalkless at stem-tips. They spiral up the cream or lemon-yellow young branches, sometimes alternate or sub-opposite.
The leaf-shape is narrowly oblanceolate or oblong, often slightly wider near the pointed tips where they may fold in slightly, occasionally markedly. The leaf margins are entire and thickish, in picture yellowish near the leaf tips.
The blade surfaces may be smooth or finely hairy. In picture grey-green to blue-green, the blades may also be yellower green or fairly grey. The midrib may show slightly on the lower surface. Leaves become about 10 mm long and 5 mm wide (Vlok and Schutte-Vlok, 2015; Shearing and Van Heerden, 2008; Manning and Goldblatt, 1997; Bond and Goldblatt, 1984; iNaturalist; http://pza.sanbi.org).