Description:

• Perennial undershrubs but sometimes flowering in herbaceous state, low, with or without elongated and often procumbent branches, sometimes cushion-forming or tufted, mostly woody at base
• Leaves alternate, usually densely crowded on long or short shoots, linear, lanceolate, elongated or spathulate, entire, 1-nerved, midrib sometimes persistent and spinescent
• Flowers solitary in leaf axils or in short axillary cymes, sessile or subsessile, bibracteolate, dark blue to violet
• Calyx tubular, 5-lobed to various depths; tube campanulate; lobes linear to deltoid or ovate, ± valvate in bud
• Corolla tubular, slightly irregular, 5-lobed; tube elongated, much longer than calyx, widening suddenly above short, narrow base into a long throat, mouth wide; limb patent, much shorter than tube, oblique; lobes free, rounded, ± equal, 2 posterior outside in bud
• Stamens 4, didynamous, included, arising in lower part of corolla tube; filaments filiform; anthers of shorter, posterior pair smaller than those of longer, anterior pair and sometimes sterile, anthers bithecate, transverse, ciliate-hispid; thecae confluent so dehiscing along a single transverse line
• Nectary usually saucer-shaped
• Ovary bilocular; ovules many; style filiform, exceeding stamens; stigma small, obscurely bidentate, emarginate or subcapitate
• Fruit a thick-walled capsule, obovoid, ± globose, broadly ovoid or ovoid, upper part compressed at right angles to septum, emarginate, septicidal but opening only at top, often persistent; valves usually bifid
• Seeds many, obovoid or flattened-globose; testa adpressedly reticulate

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:

• Aptosimum Burch. ex Benth.
  • Bentham: t. 1882 (1836) name conserved
  • Hiern: 125 (1904)
  • Hemsley & Skan: 267 (1906)
  • Weber: 1 & tt. 1-3 (1907)
  • Merxmüller & Roessler: 12 (1967)
  • Codd: 80 (1982)
  • Philcox: 3 (1990)
• Chilostigma Hochst.
  • Hochstetter: 372 (1841)
• Ohlendorffia Lehm.
  • Lehmann: 7 (1835)

Distribution & Notes:

• Global: Species ± 40, native to southern and tropical Africa
• Southern Africa: Species ± 19, widespread but mostly in western, dry regions; not in Swaziland, KwaZulu-Natal or Lesotho