Description :

• Annual or perennial herbs, with erect, ascending or procumbent stems
• Leaves digitately 3(5-9)-foliolate; leaflets dentate or entire; stipules adnate to petioles, entire or sometimes dentate
• Flowers white, yellow, purple, pink, flesh-coloured, lilac, violet or 2-coloured, pedicellate or sessile, in spikes, heads, or umbels, rarely solitary; bracts small or 0
• Calyx often with campanulate tube, 5-10(-36)-nerved; lobes variable
• Corolla persistent; petals all, or lower 4, ± adnate to staminal tube; vexillum sessile; wings oblong, eared, clawed; keel oblong or planoconvex, clawed
• Stamens diadelphous; vexillary stamen free or partly connate with rest; filaments sometimes all, or alternate ones, broadened; anthers uniform
• Ovary sessile or subsessile, 1-12-ovuled; style straight and incurved above, with capitate stigma
• Pod ovate or oblong, compressed or subterete, indehiscent within calyx or opening by sutures
• Seeds 1 or 2(4), globular to ovoid and oblong, sometimes reniform to lenticular
• x = 7, 8 (5, 6, 9) (polyploidy, B-chromosomes)

Nomenclature:

• Trifolium L.
  • Linnaeus: 764 (1753)
  • Harvey: 158 (1862)
  • Gillett: 1016 (1971)
  • Zohary & Heller: 53 (1984)

Distribution & Notes:

• Global : Species ± 250, cosmopolitan in temperate and subtropical regions of the northern and southern hemispheres
• Southern Africa : Species 19, including some introduced and widespread ones, mainly near cultivation