Trifolium rueppellianum Fres.
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Leguminosae

Synonyms

T. subrotundum Hochst. and Steud. in part; T. goetzenii auct., non Taub. ex Engl.; T. preussii Taub.

Common names

Rueppell's clover.

Description

An erect or occasionally prostrate annual. Stems glabrous, not rooting at the nodes. Leaves glabrous or nearly so. Stipules up to 15 mm long, with three to four nerves, united with the petiole for two-thirds of their length, tips entire, acuminate. Petiole only a few millimetres long and sometimes wholly adnate to the stipules in the upper leaves, up to 5 cm long in the lower leaves. Leaflets oval, oblong or obovate, rarely broadly-lanceolate, less than three times as long as wide, rounded truncate or, less often, emarginate at the tips, rarely acute, up to 24 mm long and 14 mm wide. Teeth strongly developed, up to 0.5 mm long, often with subulate tips, 10 to 15 main nerves on each side, at an angle of 40 to 50° to the midrib. Inflorescence more or less globose, typically 15- to 30-flowered and c. 17 mm across, sometimes few flowered in stunted plants, especially at high altitudes. Peduncles pilose near the top, many times longer than the subtending petiole, bracts minute or linear-lanceolate, up to 3 mm long. Pedicels glabrous, pilose, up to 2 mm long, shorter than the calyx tube, suberect in fruit. Calyx glabrous, except occasionally for a few hairs at the margins; tube pale, rounded at the base, strongly 11 nerved, the commissural nerves almost always undivided to the top. Teeth abruptly narrowed near the base, subulate for most of their length, 2 to 5 mm long, sometimes exceeding the corolla. Corolla purple, rarely white, wings with a well-developed auricle. Pods 3 to 4 mm long by 2 mm wide. Two to three seeds, occasionally four to five, oval, brown, c. 1.5 x 1 mm (Gillett, Polhill and Verdcourt, 1971).

Distribution

There are two varieties.
  • Var. rueppellianum: 
occurs from Uganda, Kenya and Tanzania through eastern Zaire to Fernando Póo (Equatorial Guinea) and Cameroon, as well as in the Sudan and Ethiopia, mainly in upland grasslands, moorlands, tracks through upland forests and as a weed in cultivated areas. It usually occurs in rather wet places, from 1 600 to 3 600 m in elevation, with an annual rainfall of from 650 to 1 200 mm. It is the most usual form, common in seasonal swamps.
  • Var. minimiflorum Gillett: 
is known only from the Moshi District of Tanzania, where it occurs in grasslands from 1 000 to 1 800 m in elevation, with up to 2 000 mm annual rainfall (Gillett, Polhill and Verdcourt, 1971).

General features

Next to T. semipilosum, T. rueppellianum is the East African clover showing the most potential for domestication. Like T. semipilosum, it has a wide range of ecotypes, is easily grown from seed and reseeds itself readily, persisting well in association with perennial grasses in appropriate habitats. Seed yields of over 224 kg./ha have been harvested by direct heading, even though the pods shatter readily (Bogdan, 1956).
Palatability can be rather low when the plants are young but improves as they reach maturity (Strange, 1958) . One form is cultivated in Ethiopia as forage for horses (Gillett, 1953).

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