Orbea melanantha (Schltr.) Bruyns

Succulent forming mat to 1 m diam., not rhizomatous. Stems 30-100 mm long, (10-)15-40 mm thick (excluding teeth), usually very stout, decumbent, pale green speckled with red-brown; tubercles 6-15 mm long, joined into 4 continuous obtuse wing-like angles along stems with deep groove between angles, laterally flattened, tapering into stout deltoid acute tooth with small denticle on either side near tip, tip gradually becoming hardened and covered with yellowish corky layer. Inflorescence 1(-2) per stem near or above middle, of 3-13 simultaneously opening flowers from stout peduncle up to 15 mm long and 6-10 mm thick, with lanceolate to ovate laterally toothed subulate bracts 4-8 mm long; pedicel 15-45 mm long, 3-4 mm thick, ascending to spreading; sepals 6-10 mm long, 2-3 mm broad at base, ovate-lanceolate, acuminate. Corolla 40-65 mm diam., rotate; outside smooth, pale cream suffused with brown; inside deep red-brown to maroon-or purple-black sometimes finely spotted with yellow, finely rugulose on lobes becoming deeply ± concentrically rugulose in tube, surface finely papillate all over with occasional larger spike-like papillae up to 1 mm long; tube 2.5-4.0 mm deep, short, cupular, containing ± whole of gynostegium, with corolla much thickened at mouth; lobes 14-18 mm long, 9-14 mm broad at base, broadly deltate-ovate, acute, spreading with tips often reflexed, with vibratile clavate purple cilia 2-5 mm long along margins. Corona ±3 mm tall, 8-9 mm broad, raised above base of tube by stout pentagonal stipe <1 mm long, red-brown to purple-black; outer lobes 3-4 mm long, 3 mm broad, ascending-spreading, flat, ± square (often widening towards apex) with 2 or more often spreading short apical teeth, above with 2-3 radial raised tuberculate ridges; inner lobes 2-3 mm long, adpressed to backs of anthers for ± half anthers’ length then ascending and nearly equalling them, dorsiventrally flattened near base with raised crenulate margins (so concave there) becoming laterally flattened above, with erect to slightly recurved dorsal horn just behind somewhat obtuse ± horizontal apex (apex sometimes absent below dorsal horn) and second dorsal horn occasionally present, with dorsal tuberculate ridges and horns confluent with outer series towards base.