Some 47 species of Tylecodon are endemic to South Africa and Namibia (Van Jaarsveld & Koutnik 2004). In South Africa 43 species occur, confined to the south – and south-western portion of the country where winter rainfall is experienced. The new species falls within the Knersvlakte Centre of Plant Endemism (Van Wyk & Smith 2001). Tylecodon opelii is a new, obligate quartz-gravel dwelling species endemic to the northern Knersvlakte in the northern part of the Western Cape Province of South Africa. It was discovered by, and is named for, Conophytum expert Matt Opel, of the University of Connecticut (USA), on a expedition to the Knersvlakte July 2000. It is related to a group of dwarf, quartz-dwelling, geophytic species growing mainly in Succulent Karoo vegetation: Tylecodon nolteei, T. occultans, T. pusillus and T. peculiaris. Tylecodon opelii is immediately distinguished from other species by its oblong tubers, and its irregularly moulded leaves, which are intensely dark green during the growing season, bearing a few pointed trichomes. The corolla of T. opelii is cylindric to slightly funnel-shaped, 12-14 mm long, with tapering squamae at the base. The species can be confused with T. occultans and T. nolteei. However, T. occultans is immediately recognised by the white whiskery trichomes on its much broader leaf surfaces, T. nolteei (Fig. 1) by its blood-red, Gorbachev-forehead markings. T. occultans and T. opelii never have these painted markings, and T. nolteei has a larger, much taller caudex, though that pertains more to plants at the type locality; the eastern and southern populations show rounder, more modest caudexes. Tylecodon peculiaris (Fig. 2) is another very little-known plant with which T. opelii can also be confused, but it is immediately distinguished by its rough ‘jellytot’ appearance, the epidermis having a glassily bubbled purplish-green texture. Tylecodon opelii Van Jaarsv. & S.A.Hammer, differt a T. occultante tuberibus oblongis, foliis atroviridibus, irregulariter contortis, trichomata acuta sparse ferentibus, corolla 12–14 × 2–3 mm ad orem tubo alba differt. TYPE.—SOUTH AFRICA 3118 (Vanrhynsdorp): Bakoondkolk, south-sloping quartz gravel hillside, 150–200 m, (–AB), Van Jaarsveld 22751 (NBG, holo.). Plant solitary, summer-deciduous, dwarf geophyte to 10 mm in diameter. Roots fibrous. Tuber oblong, up to 35 × 10–15 mm, pale grey-brown and somewhat flaking, exposing the grey-green epidermis underneath; phyllopodia absent. Leaves softly succulent, apically produced, solitary or rarely with up to 3 leaves, ascending; blade irregularly molded, broadly club-shaped, orbicular to reniform (viewed from the top), often irregularly concave or shallowly grooved, 8–15 × 10–15 mm, cuneate and