Platostoma rotundifolium

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Platostoma rotundifolium
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Lamiales
Family: Lamiaceae
Genus: Platostoma
Species:
P. rotundifolium
Binomial name
Platostoma rotundifolium
(Briq.) A.J.Paton
Synonyms [2]
  • Geniosporum affineGürke
  • Geniosporum angolenseBriq.
  • Geniosporum paludosumBaker
  • Geniosporum rotundifoliumBriq.
  • Geniosporum scabridumBriq.
  • Ocimum konianenseA.Chev.
  • Ocimum paludosum(Baker) Roberty
  • Plectranthus etiolatusChiov.

Platostoma rotundifolium is a species of jellywort native to much of sub-Saharan Africa. [2]

Contents

Description

This species is a perennial herb or small shrub growing 0.6–1 m (2 ft 0 in – 3 ft 3 in) tall. It arises from a horizontal woody rhizome and is not known to be aromatic. The stems are erect, square in cross-section, and branch mainly in the upper parts. They are covered with short hairs, which may point upwards or backwards, and scattered small surface glands. [3] [4]

The leaves are stalked and often bend downwards. The leaf blades are ovate to oblong, measuring 15–85 mm (0.59–3.35 in) long and 10–35 mm (0.39–1.38 in) wide. They have serrated to scalloped margins that are often slightly rolled under, with blunt tips and bases that are heart-shaped or wedge-shaped. The leaves are hairy to densely hairy and bear scattered surface glands; the upper leaves are frequently white, pink, or purplish in colour. The leaf stalks are short, about 3–10 mm (0.12–0.39 in) long. [3]

The inflorescence is dense, with many-flowered whorls packed closely together so that they touch. The upper bracts are green and upright, forming a small terminal tuft, while the lower bracts are white, pink, or purple, spreading or bending downwards and becoming leaf-like. The flower stalks are slightly flattened and 2–3 mm (0.079–0.118 in) long. [3]

The calyx is very small, only 1–1.5 mm (0.039–0.059 in) long at flowering, and densely hairy with surface glands. It enlarges to 2–3.5 mm (0.079–0.138 in) in fruit. The throat is partly closed by the shape of the calyx lobes. The corolla is white or purple, 3–5 mm (0.12–0.20 in) long, with a short tube. The stamens protrude slightly beyond the corolla, up to 2 mm (0.079 in). [3]

The ovary is smooth. The fruits consist of dark brown, obovoid nutlets about 1 mm (0.039 in) long, with fine longitudinal ridges and usually smooth surfaces, though young nutlets may bear small hairs. [3]

Distribution and habitat

Platostoma rotundifolium is widespread in tropical Africa, where it grows in grassland (especially where prone to flooding), alongside streams, and in other marshy places. It has been recorded in Angola, Benin, Burundi, Cameroon, the Republic of the Congo, the Democratic Republic of the Congo, Eswatini, Ethiopia, Guinea, Ivory Coast, Kenya, Malawi, Mozambique, Nigeria, Rwanda, Sierra Leone, South Africa, South Sudan, Tanzania, Uganda, and Zambia. [2] [5] [4]

References

  1. "Platostoma rotundifolium (Briq.) A.J.Paton". Red List of South African Plants. SANBI. Retrieved 2026-01-22.
  2. 1 2 3 "Platostoma rotundifolium (Briq.) A.J.Paton". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 22 January 2026.
  3. 1 2 3 4 5 Paton, A.J.; Bramley, G.; Ryding, O.; Polhill, R.M.; Harvey, Y.B.; Iwarsson, M.; Willis, F.; Phillipson, P.B.; Balkwill, K.; Lukhoba, C.W.; Otieno, D.F.; Harley, R.M. (2009). Flora of Tropical East Africa: Lamiaceae (Labiatae). Kew: Royal Botanic Gardens, Kew. pp. 231–232. ISBN   978 1 84246 372 7 . Retrieved 15 January 2026.
  4. 1 2 Codd, L. E. W., Dyer, R. A., Rycroft, H. B., de Winter, B. (1985). Flora of Southern Africa: The Republic of South Africa, Basutoland, Swaziland and South West Africa. Vol. 28. Govt. Printer. p. 215. ISBN   0621082686.
  5. Klopper, R. R.; Winter, P. J. D., eds. (20 March 2025). "The South African National Plant Checklist: 2025 official yearly release". South African National Biodiversity Institute (SANBI). Retrieved 21 January 2026.

See also