Orbea melanantha

Orbea melanantha, previously Caralluma melanantha, C. leendertziae, C. australis and commonly the black-flowered caralluma, is a clump-forming stem succulent reaching heights up to 10 cm.

The four-angled stems are markedly toothed. The stems become up to 2 cm in diameter, the teeth adding up to another 1 cm on either side. Tiny denticles or side-teeth grow in pairs near the tooth tips.

Flowers grow in umbels of up to five from peduncles emerging at the mid-parts of stems. Each flower pedicel may be about 4 cm long. Hairless sepals, ovate to lanceolate in shape grow at the flower base, becoming 9 mm long and 3 mm wide.

The five-pointed corolla has short triangular lobes that may recurve. The outside of the corolla is hairless and smooth, the inside wrinkled and sparsely covered in purple-black long hairs. The vibratile and club-shaped hairs are the same colour as the inner corolla surface. The hairs continue as cilia like eye-lashes along the corolla margins. Some tiny yellow spots are scattered on the corolla of the flower in picture.

The outer corona is five-lobed, hairless and brownish-purple with ascending and spreading lobes, two-keeled near their tips that are three-toothed. The dark purple inner corona has converging lobes attached below to the outer corona and sometimes notched at their tips.

Flowering happens during summer and autumn.

The species is distributed in Gauteng, Limpopo and Mpumalanga, as well as in Mozambique. The plant grows on stony ground near and under shrubs, typically at elevations above 1000 m. The species is not considered to be threatened in its habitat early in the twenty first century (White and Sloane, 1937; http://llifle.com; www.redlist.sanbi.org).