Description :

• Herbs or undershrubs, sometimes with tuberous roots
• Leaves opposite or rarely ternate, coarsely crenate or dentate to subentire
• Inflorescences terminal, spike-like, on main and sometimes on upper lateral branches; bracts small, persistent; flowers 1-6 in axils of each bract, forming 2-12-flowered verticils 10-20 mm apart
• Calyx 5-toothed, 2-lipped; tube cylindric to campanulate; upper tooth broadly ovate-orbicular with margin ± decurrent on tube; lower teeth subequal, ovate-deltoid, acuminate to subulate, 2 lowest usually longer than 2 laterals
• Corolla bilabiate; tube narrowly to broadly cylindric, straight or curved; upper lip erect, 3- or 4-lobed; lower lip horizontal to recurved, concave to boat-shaped
• Stamens 4, free, didynamous, declinate, exserted; lower pair arising near mouth; upper pair arising further back in corolla tube; filaments glabrous or pilose at base; anthers 1-thecous
• Disc saucer-shaped, often with a ventral lobe
• Style filiform, ± capitate, lying together with and subequal to stamens
• Nutlets suborbicular to oblong, glabrous
• x = 7 (6, 11, 13) (polyploidy)

Nomenclature:

• Orthosiphon Benth.
  • Bentham: t. 1300 (1830)
  • Bentham: 25 (1832)
  • Bentham: 49 (1848)
  • Bentham 1174 (1876)
  • Briquet: 372 (1897)
  • Baker: 365 (1900)
  • Brown: 237 (1910)
  • Morton: 454 (1963)
  • Codd: 229 (1985)
• Nautochilus Bremek.
  • Bremekamp: 253 (1933)

Distribution & Notes:

• Global : Species 40-50, in the tropics of the Old World
• Southern Africa : Species 9, Botswana, Northern Province, Mpumalanga, Swaziland, KwaZulu-Natal and Eastern Cape