Description:

• Aquatic or marsh herbs, annual or perennial; aerial stems simple to much branched, glabrous or sometimes hirsute, often with pellucid dots and aromatic; submerged stems much branched, glabrous
• Leaves: aerial ones opposite or verticillate, sessile, entire to serrate, laciniate or pinnately divided, punctate; submerged leaves laciniate, pinnatifid to capillary-multifid, glabrous
• Flowers solitary and axillary, or in a dense, terminal raceme, sessile or pedicellate, bracteate; bracteoles 0 or 2
• Calyx tubular, 5-lobed mostly to ± halfway, rarely shorter; lobes broadly ovate to lanceolate, sometimes acuminate, imbricate, subequal or posterior lobes larger
• Corolla tubular, bilabiate, 5-lobed; tube cylindrical or funnel-shaped, glabrous or sparsely hirsute outside, sometimes villous or papillate inside; posterior lip entire or 2-lobed, outside in bud; anterior lip 3-lobed; lobes elliptical or ovate, slightly or much shorter than tube, erect or spreading
• Stamens 4 (sometimes 2 in cleistogamous flowers), didynamous, included, posterior pair shorter; filaments linear, arising in corolla tube; anthers bithecate, free, sometimes contiguous at anthesis; thecae separate, usually shortly stalked; staminodes 0
• Ovary bilocular, ovoid, glabrous; ovules many; style filiform, bent at right angles at apex; stigma bilamellate
• Fruit an ovoid or ellipsoid, septicidal and loculicidal capsule, with 2, often bifid valves
• Seeds small, many, ellipsoid; testa thin, dark-coloured
• x = 17 (9, 15) (polyploidy)

Nomenclature:

• Limnophila R.Br.
  • Brown: 442 (1810) name conserved
  • Merxmüller & Roessler: 25 (1967)
  • Philcox: 101 (1970)
  • Greuter et al.: 289 (1994)
  • Philcox: 43 (1990)
  • Mielcarek: 50 (1996)

Distribution & Notes:

• Global: Species 37, Old World tropics and subtropics, Africa, Asia, and Australia
• Southern Africa: Species 2, Namibia, Botswana and Mpumalanga (Kruger National Park); usually aquatic or amphibious, in shallow water or mud of bogs, swamps or riversides