Cleome L.
Genus with some 206 species currently recognised (from the originally 600 species described) distributed mainly in tropical regions, desert or semidesert, in America, Asia and Africa, with its distribution end reaching the Mediterranean region. They are glandular herbaceous, annual or perennial plants, sometimes woody at the base, or small shrubs, with simple or compound leaves. There are about 10 species in North Africa, 4 of them are more or less woody.
The other taxa of the genus that are somewhat woody at the base, are herbaceous annuals, biennials or shortly perennials, rarely exceeding 40 cm in height. They grow in sandy or stony wadis and plains (ergs, regs), they often behave as ruderal species. They are distributed in the Sahara and neighboring areas up to Iran. Four of these species can be identified by their larger size and slightly lignified base of the stems.
With dark purple flowers, linear leaves, lanate seeds and fetid odour: C. arabica L. (Ara.: zelta), with predominantly simple leaves, only some trifoliolate, fruit >5 cm and densely lanate seeds (hair length = diameter); and C. amblyocarpa Barratte & Murb., (C. africana Botsch.) (Tamahaq: Aoyyagh), with leaves 3-5 foliolate, fruit <5 cm and less lanate seeds (hairs 1/2 the diameter).
A further 2 species with yellow petals and seeds not lanate, also somewhat lignified at the base, are: C. viscosa L. (Ara.: abu tarbush, Tamahaq: adagall nagasaye, n-aegasay), with long fruit (4-7 cm), linear, 8-20 stamens and rugose brown seeds; and C. brachycarpa DC., with a shorter fruit (less than 1 cm), 6 stamens and smooth grey seeds.
Rare but widely distributed species. Currently, they have not been assessed at a global level in the IUCN Red List of Threatened Species. In the Red List of vascular plants of Egypt (Flora Aegyptiaca Vol 1, 2000) C. viscosa is listed as “Rare”.
Key to species
1 Subshrubs or small woody shrubs with simple leaves 2
1 Perennial herbaceous plants with rootstock and base of stems ± woody. Compound leaves often palmate, with (1)3-5(7) leaflets 3
2 Fruits erect-patent, with straight peduncle. Leaves ± orbicular with 3 veins. Stamens 4-6 Cleome droserifolia
2 Fruit pendant, with curved peduncles. Leaves ovate, somewhat acuminate. Stamens 10-14 Cleome chrysantha
3 Evergreen plant, robust, tall (0.5-2 m) with rootstock and base of stems woody. Leaflets linear. Capsules >10 cm 4
3 Herbaceous plant, shorter in height, somewhat lignified at the base, with ovate or lanceolate leaflets. Capsules 5
4 Leaflets 1-3 cm. Flowers about 4 mm, with white or pale yellow petals. Capsules 3-5 cm long Cleome tenella
4 Leaflets 5-10 cm. Flowers about 3-4 cm, with yellow petals, sometimes Cleome paradoxa
5 Petals dark purple, fruits villous 2-5 cm long, fetid smelling plants, with ± lanate seeds at maturity 6
5 Petals yellow, seeds not lanate 7
6 Leaves 3-5 foliolate, fruit C. amblyocarpa
6 Leaves predominantly simple, just a few trifoliolate, fruit >5cm and seeds densely lanate (hairs of equal length as the diameter of the seed) C. arabica
7 Fruit long (4-7 cm), linear, 8-20 stamens, rugose brown seeds C. viscosa
7 Fruit short less than 1 cm, 6 stamens, smooth grey seeds C. brachycarpa
Updated by: H. Sainz & J. Charco.