Description:

• Perennial soft shrubs or annual herbs, or stems arising annually from a perennial woody rootstock
• Leaves opposite or rarely ternate, sessile or petiolate, usually toothed
• Inflorescences terminal, spike-like, paniculate; verticils crowded or lax, 2-6-flowered; bracts small and caducous or persistent, or terminal few pairs large and persistent as a colourful coma
• Calyx bilabiate, 5-toothed, uppermost tooth broadly ovate to subrotund, decurrent on tube; 2 lower teeth subulate to spinescent, longer than 2 lateral, deltoid-lanceolate teeth
• Corolla bilabiate; tube subcylindrical or widening slightly to the truncate mouth; upper lip short, erect, obscurely 3- or 4-lobed; lower lip longer than upper, concave, horizontal to deflexed
• Stamens 4, didynamous, usually exserted; upper pair arising near or below middle of corolla tube, filaments free, usually pubescent near base and sometimes higher as well; lower pair arising at corolla mouth, filaments connate for all or part of their length (occasionally almost free), glabrous
• Disc usually crenate, produced in front
• Style exserted, minutely bifid or occasionally clavate
• Nutlets ovoid
• x = 7 (1 report) (polyploidy)

Nomenclature:

• Hemizygia (Benth.) Briq.
  • Bentham: 41 (1848)
  • Briquet: 368 (1897)
  • Launert & Schreiber: 11 (1969)
  • Codd: 193 (1985)
• Ocimum sect. Hemizygia Benth.
  • Bentham: 41 (1848)
• Orthosiphon in sense of Baker
  • Baker: 365 (1900) in part
• Orthosiphon in sense of N.E.Br.
  • Brown: 237 (1910) in part
• Bouetia A.Chev.
  • Chevalier: 200 (1912)

Distribution & Notes:

• Global: Species ± 35, mainly in Africa
• Southern Africa: Species 28, northern parts of Namibia and Botswana, but most species found in Northern Province, Mpumalanga and also in Gauteng and North-West; a few species in KwaZulu-Natal and Eastern Cape