Tromotriche revoluta (Masson) Haw.

Few-stemmed to clump-forming succulent up to 1 m diam, sometimes forming large patches (to 2-3 sq m in extent) of scattered single stems. Stems 40-200(-500) mm long, 15-30 mm thick (usually cylindrical and at most 10 mm thick below ground), decumbent, often spreading horizontally underground for up to 1 m, above-ground parts pale bluish green to grey-green; tubercles 2-3 mm long, joined into 4 broad obtuse angles along stem, each tipped with small deltoid tooth (<1 mm long) flanked by 2 minute denticles, tooth and denticles with time becoming covered with grey cork-like callus. Inflorescence 1(-3) per stem arising towards apex, bearing 1-2 flowers developing in gradual succession ± without peduncle, with few short deltoid acute bracts 1.5-2.5 mm long; pedicel 5-15 mm long, 2-3 mm thick, spreading and holding flower facing horizontally; sepals 6-8 mm long, 1.5-2.0 mm broad at base, lanceolate, acute. Corolla (30-)40-50(-70) mm diam., ± turban-shaped; outside pale green suffused with red; inside yellow to red-brown becoming paler to cream on annulus and in tube, smooth and somewhat shiny, with fine acute papillae in base of tube; tube ±5 mm long, 6-10 mm broad, pentagonal to circular at mouth, cupular and much constricted at mouth by massive overhanging ledge of annulus, formed entirely by much thickened annulus in otherwise ± flat central part of corolla; lobes 14-18 mm long, 14-18 mm broad at base, strongly folded back behind flower to give it turban-like shape, broadly ovate, acute, margins slightly recurved so that upper surface slightly convex, with purple vibratile clavate cilia 2-3 mm long all along margins. Corona ±10 mm tall, 8 mm broad, raised on stout pale yellow stipe up to 2 mm long; outer lobes 2-3 mm long, ±2 mm broad, ascending, often ± rectangular, obtusely bifid to tridentate or nearly truncate, channelled down inner surface, dark brown becoming yellow around bases; inner lobes 5-6 mm long, adpressed to backs of anthers then erect for short distance then recurved, dorsiventrally flattened towards base then terete and swelling into clavate-tuberculate apex, usually with spreading laterally flattened narrowly deltoid horn 1-4 mm long near base, brown to yellow speckled with purple.