Description:

• Annual or perennial herbs or subshrubs
• Leaves thin or thick-textured, entire or toothed
• Inflorescences usually simple, of few to many, spaced or fairly crowded verticils; verticils 2-many-flowered, often in glomerate clusters; bracts leaf-like, often smaller towards apex of inflorescence; bracteoles linear, ascending, small or conspicuous
• Calyx shorter or longer than corolla tube, tubular or tubular-campanulate, rarely inflated, 10-nerved, straight or curved, sometimes oblique at mouth; teeth 5-10, equal or unequal, often spine-tipped
• Corolla bilabiate, white; tube tubular, widening above, sometimes shortly constricted at base, annular-pilose or annular-papillose within, rarely glabrous; upper ascending or spreading, concave or flattish, entire or rarely emarginate or 2-lobed, longer than, subequal to or shorter than lower lip, usually with stiff brush-like hairs; lower lip spreading or deflexed, 3-lobed, median lobe the largest
• Stamens 4, didynamous, lower pair longer than upper, ascending under the upper lip, included or shortly exserted; anthers approximate in pairs, 2-thecous with the thecae divaricate and finally confluent
• Style terete, ascending under upper lip, unequally 2-lobed at apex
• Nutlets ovoid-triquetrous, smooth, obtuse or somewhat flattened at apex
• x = 11, 7 (polyploidy)

Nomenclature:

• *Leucas R.Br.
  • Brown: 504 (1810)
  • Bentham: 523 (1848)
  • Bentham: 1212 (1876)
  • Briquet: 250 (1896)
  • Baker: 472 (1900)
  • Skan: 369 (1910)
  • Launert & Schreiber: 16 (1969)
  • Codd: 39 (1985)
• Lasiocorys Benth.
  • Bentham: 600 (1834)
  • Bentham: 534 (1848)
  • Bentham: 1213 (1876)
  • Baker: 469 (1900)
  • Skan: 372 (1910)
  • Phillips: 645 (1951)

Distribution & Notes:

• Global: Species ± 150, mainly in tropical Africa and Asia
• Southern Africa: 7 species are widespread but do not occur in the winter-rainfall region and adjacent areas