Origin and Habitat: South Namibia, and north-western Republic of South Africa (Little Namaqualand)
Habitat and ecology: It grows in very arid areas often beneath large Aloe dichotomaSN|616]]SN|616]] trees.

• Piaranthus cornutus N.E.Br.
• Piaranthus decorus var. cornutus (N.E.Br.) Meve

• Piaranthus cornutus N.E.Br.
• Piaranthus decorus var. cornutus (N.E.Br.) Meve
• Piaranthus cornutus var. grandis N.E.Br.
• Piaranthus nebrownii Dinter
• Piaranthus pulcher var. nebrownii (Dinter) A.C.White & B.Sloane
• Piaranthus pallidus C.A.Lückh.
• Piaranthus pulcher N.E.Br.

• Piaranthus cornutus var. mennellii (C.A.Lückh.) Plowes
• Piaranthus mennellii C.A.Lückh.

• Piaranthus cornutus var. ruschii (Nel) Bruyns
• Piaranthus ruschii Nel

Description: Piaranthus cornutusSN|30433]]SN|30433]], the 'Horned Piaranthus' from the prominent corona lobes in the middle of the flower, is a clumping and prostrate species that spread over the ground forming large cushions of short-jointed brownish-green stems. The starfish-like flowers form in small bunches at the tips of the young stems, brownish-yellow, pale yellowish, or whitish on the inner face and heavily mottled with dark red.
Taxonomy: This is plant is often placed together with Piaranthus decorusSN|18048]]SN|18048]] (Piaranthus decorusSN|18048]]SN|18048]] subsp. cornutus), but the corona is quite different. Piarnthus decorus has outer corona lobes incumbent on the anthers with extremely large deeply furrowed crests, in Piaranthus cornutusSN|30433]]SN|30433]] the outer-corona lobes are erect and the crests are more delicate.
Stems: Procumbent or ascending, 1.5-5 (or under cultivation up to 8) cm long, 12-18 mm thick, globose, ovoid, oblong or cylindrical, very obtusely 4-angled, with 3–5 tubercle-like teeth along the angles, greyish- or glaucous-green often becoming brownish-green in full sun.
Flowers: 1- to several, but usually in pairs, above the middle or at the tips of the stems, erect, scentless or with sweetish odour of decaying fruits. Pedicels (4-)6-12(-18) mm long, 1-1.5 mm thick, glabrous. Sepals 2-4 mm long, lanceolate, acute, glabrous. Corolla 15-28 mm in diameter, very deeply lobed, without a distinct tube. Corolla lobes about c 10 mm long, 3-5 mm broad at the base, more or less free, lanceolate, acuminate, often some-what ascending (at an angle of ± 30°), tips often re-curved, glabrous on the back, velvety-puberulous on the inner face, brownish-yellow, pale yellowish, or whitish, with purple, crimson or brown dots, patches or tranverse bands (rarely with-out pattern), densely hairy. Hairs conical, white to purple-brown, 0.1-1 mm long. Corona 2.5-3(-3.5) x 3.5-4.7 mm. Outer corona-lobes about 1.2-2 mm long, 0.5-0.8 mm thick, narrowly linear-lanceolate or lanceolate-subulate, incumbent at the base upon the backs of the anthers and produced beyond them into connivent-erect acute tips, dorsally produced at the base into a subquadrate crest, 0.8-1.5 mm broad, truncate and tuberculate-denticulate at the top, yellow, without markings. Pollinia 0.45-0.6 x 0.28-0.35 mm.
Fruits (paired follicles): About 10 cm long.
Seeds: Mostly 5 x 3 mm.

Bibliography: Major references and further lectures
1) N. E. Brown. “Flora Capensis”, Vol 4, page 518, 1909
2) Focke Albers, Ulrich Meve “Illustrated Handbook of Succulent Plants: Asclepiadaceae: Asclepiadaceae” Volume 4 Springer Science & Business Media, 2002