Description :

• Low undershrubs, sometimes flowering in herbaceous state; branches slender, usually fairly stiffly erect, longitudinally striated from decurrent leaf bases, sometimes viscid
• Leaves alternate, crowded or scattered, linear, elongated, elliptical, ovate or obovate, sessile to shortly petiolate, entire, 1-nerved, ± densely or sparsely papillose, almost glabrous or finely glandular-tomentose
• Flowers solitary in leaf axils, very shortly pedicellate with 2 small bracteoles at base, dark blue to violet
• Calyx divided almost to base, 5-lobed, ± valvate; lobes linear, narrow, acute
• Corolla tubular, weakly irregular, 5-lobed, much longer than calyx; tube elongated, narrow below then widening suddenly, throat long, mouth wide; lobes ± equal, free, rounded, spreading, shorter than tube, posterior pair outside in bud
• Stamens 4, didynamous, included, arising in lower part of corolla tube; filaments filiform; anthers of equal size, all fertile, transverse, usually ciliate; thecae confluent
• Ovary bilocular, ± narrowly ovate; ovules many; style filiform, exceeding stamens; stigma small, entire, emarginate or slightly bilobed
• Fruit a thin-walled capsule, narrowly elongate-ovoid, acute, acuminate or obtusely pointed, somewhat compressed at right angles to septum, bisulcate over septum, longer than calyx, septicidally bivalved, opening ± to base; valves deeply bilobed
• Seeds rugose or scrobiculate-tuberculate

Classification Notes:

• There has been much controversy over separation of Aptosimum and Peliostomum (see Phillips: 22 (1950), Roessler: 9 (1966) & Philcox: 1 (1990)). Here Merxmüller & Roessler (1967) have been followed. Using the key, 2 species, A. lugardiae (N.E.Br.) E.Phillips and A. junceum (Hiern) Philcox, will key out under Peliostomum because of the fruit type. These species would appear to be better placed there. They can be distinguished because A. lugardiae has the corolla tube expanding within the calyx, lower down than in current Peliostomum species, and A. junceum has almost leafless branches

Nomenclature:

• Peliostomum Benth.
  • Bentham: t. 1882 (1836)
  • Hiern: 132 (1904)
  • Weber: 1, 80, t. 3 (1907)
  • Phillips: 22 (1950) under Aptosimum
  • Roessler: 9 (1966)
  • Merxmüller & Roessler: 37 (1967)

Distribution & Notes:

• Global : Species ± 5, Africa; most in southern Africa
• Southern Africa : Widespread, but mostly in western, dry regions; not in Gauteng or Lesotho