Description:

• Annual or perennial, often hemiparasitic herbs, usually somewhat rigid and scabrid, turning dark on drying; stems erect, ascending or prostrate, simple or branched, glabrous to hispid-scabrid
• Leaves usually opposite or quasiverticillate, sometimes subopposite or alternate above, sessile to shortly petiolate, 1-5-veined, lowest ones usually obovate, entire or dentate, upper ones narrow, entire or denticulate, gradually passing into bracts
• Flowers often small, sessile or subsessile in axils of upper leaves or bracts, usually bibracteolate, solitary, in terminal, compact to lax spikes or in terminal, or axillary, ± globose clusters; inflorescences often lengthen in fruit
• Calyx tubular, 4- or 5-toothed, tube cylindrical, narrow, 5- or 10(7 or 8)-veined or -ribbed; teeth short, deltoid to lanceolate-acuminate, usually scabrid on margin
• Corolla tubular, 4- or 5(6)-lobed, slightly irregular; tube slender cylindrical, longer than calyx, straight or gently curved, glabrous to softly pilose, throat sometimes densely pilose; limb shorter than tube, spreading; lobes subequal, obovate to subcircular or oblong, entire or emarginate, 2 posterior ones often a little smaller, interior in bud
• Stamens 4, slightly didynamous, subequal, arising about middle of corolla tube, subsessile or with short filaments, included; anthers unithecate, erect, dorsifixed, acute, blunt at base
• Ovary bilocular, elliptical; ovules many per locule; style terete, straight; stigma thickened or clavate, entire or emarginate, almost as long as style, included
• Fruit an ovoid to oblong, loculicidal capsule
• Seeds many, obovoid or oblong; testa membranous, reticulate, tightly investing endosperm
• x = 10 (polyploidy)

Nomenclature:

• Buchnera L.
  • Linnaeus: 630 (1753)
  • Linnaeus: 278 (1754)
  • Hiern: 391 (1904)
  • Hemsley & Skan: 373 (1906)
  • Merxmüller & Roessler: 20 (1967)
  • Visser: 82, 158, tt. 156-159 (1981)
  • Philcox: 96 (1990)
  • Mielcarek: 96 (1996)

Distribution & Notes:

• Global: Species ± 100, mostly Old World tropics and subtropics
• Southern Africa: Species ± 9, in all areas except Northern Cape but mostly in north and northeast