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This species is accepted, and its native range is Tanzania.
A specimen from Kew's Herbarium

[FTEA]

Lamiaceae (Labiatae), A.J. Paton, G. Bramley, O. Ryding, R.M. Polhill, Y.B. Harvey, M. Iwarsson, F. Willis, P.B. Phillipson, K. Balkwill, C.W. Lukhoba, D.F. Otieno, & R.M. Harley. Flora of Tropical East Africa. 2009

Type
Type: East Africa, without precise locality, Fischer 333 (B†, holo. K!, photo.)
Morphology General Habit
Aromatic perennial succulent shrub 1.5–2.5 m tall
Morphology Stem
Stems erect or ascending, rounded-quadrangular, branching, woody at base, pubescent or densely so with mostly antrorse eglandular hairs, becoming patent on the ± eglandular inflorescence axis
Morphology Leaves
Leaves spreading, thick, succulent, often with fascicles of younger leaves in axils, petiolate; blades broadly ovate or trullate or rarely rounded, 1.5–9 × 2–9 cm, serrate or crenate, apex obtuse to rounded, base broadly cuneate, truncate or subcordate, attenuate at petiole, densely pubescent to tomentose and with numerous red sessile glands; petiole 0.6–4 cm long
Morphology Reproductive morphology Inflorescences
Inflorescence lax with 6–14-flowered verticils 15–20 mm apart in fruit; cymes sessile, 3–7-flowered, dichasial at first branch producing two lateral condensed cincinni; bracts ovate, apiculate, 3–6 mm long, erect above forming a small conspicuous terminal coma, cucullate, enclosing buds, soon deciduous; pedicels 5–8 mm long
Morphology Reproductive morphology Flowers Calyx
Calyx 4–5 mm, sparsely pubescent to villose, with red sessile glands, often purplish; fruiting calyx 7–8 mm long, shortly tubular and with pedicel attached excentrically behind posterior lip; throat truncate and with scattered weak hairs on underside of posterior lip and occasionally on other lobes; posterior lip ovate to broadly elliptic, obtuse to apiculate at apex, curving upwards, decurrent; anterior lip 4-lobed, lobes lanceolate, median longer than lateral
Morphology Reproductive morphology Flowers Corolla
Corolla deep blue or bluish purple, 13–22 mm long, with scattered red glands and hairs on lobes; tube 5–8 mm long, sigmoid; posterior lip much shorter than anterior; anterior lip, 10–14 mm long, finally horizontal, deeply cucullate enclosing stamens
Morphology Reproductive morphology Flowers Androecium Stamens
Staminal filaments fused
Morphology Reproductive morphology Fruits
Nutlets dark brown, smooth, with dark gland dots, broadly ovate, slightly flattened, 1.5–2 mm long, producing copious speckled mucilage when wet.
Ecology
Rocky hillsides, grassland, roadsides; 1800–2100 m
Conservation
Least concern; Kenyan population is restricted to the Rift Valley and is fairly commonly collected. Within Kenya: EOO 17707 km2, 22 collections from 14 localities; AOO 5027.25 km2 with cell width 20.5 km, number of cells 12, 4 subpopulations based on adjacent cells; 4 subpopulations based on Rapoport distance. EOO suggests vulnerable status, but the species can grow in disturbed habitats and it is commonly collected. Over 50 individuals were seen in the lower gorge and side river valley at Hell’s Gate National Park (March 2007). There it grows on almost bare rock and is often high up and inaccessible from the ground
Note
One specimen seen without collector or number at EA from Limuru K 4. Most likely to be confused with P. barbatus var. grandis on account of the habit and large flowers. Differing in not having a densely hairy, bearded calyx throat and in the eglandular,mainly spreading indumentum of the inflorescence axis. The bracts of P. gymnostomus are also smaller and pedicels often longer. Specimens of P. barbatus from K 7 can have a spreading indumentum on the inflorescence axis but this is glandular. P. gymnostomus approaches P. asirensis J.R.I.Wood from Yemen and Saudi Arabia. This species has a similar habit, flower and inflorescence, but differs slightly in having purple rather than blue corollas, a more glandular inflorescence axis and frequently longer pedicels.
Distribution
Range: Not known elsewhere Flora districts: K3 K 4?, K5

Native to:

Tanzania

Coleus gymnostomus Gürke appears in other Kew resources:

Date Reference Identified As Barcode Type Status
Fischer [333], Tanzania Plectranthus gymnostomus K000431984 Unknown type material

First published in Bot. Jahrb. Syst. 19: 212 (1894)

Not accepted by

  • Govaerts, R. (1999). World Checklist of Seed Plants 3(1, 2a & 2b): 1-1532. MIM, Deurne. [Cited as Plectranthus gymnostomus.]
  • Govaerts, R. (2003). World Checklist of Selected Plant Families Database in ACCESS: 1-216203. The Board of Trustees of the Royal Botanic Gardens, Kew. [Cited as Plectranthus gymnostomus.]
  • Paton, A.J., Bramley, G., Ryding, O., Polhill, R., Harvey, Y., Iwarsson, M., Willis, F., Phillipson, P., Balkwill, K., Lukhoba, C., Otiend, D & Harley (2009). Lamiaceae (Labiatae) Flora of Tropical East Africa: 1-430. [Cited as Plectranthus gymnostomus.]

Literature

Kew Backbone Distributions

  • Paton, A.J., Mwanyambo, M. Govaerts, R.H.A., Smitha, K., Suddee, S., Phillipson, P.B., Wilson, T.C., Forster, P.I. & Culham, A. (2019). Nomenclatural changes in Coleus and Plectranthus (Lamiaceae): A tale of more than two genera PhytoKeys 129: 1-158.

Flora of Tropical East Africa
Flora of Tropical East Africa
http://creativecommons.org/licenses/by-nc-sa/3.0

Herbarium Catalogue Specimens
Digital Image © Board of Trustees, RBG Kew http://creativecommons.org/licenses/by/3.0/

Kew Backbone Distributions
The International Plant Names Index and World Checklist of Selected Plant Families 2021. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
© Copyright 2017 World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

Kew Names and Taxonomic Backbone
The International Plant Names Index and World Checklist of Selected Plant Families 2021. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
© Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0