Lamiaceae
Leucas

Leucas nubica Benth.

First published in A.P.de Candolle, Prodr. 12: 530 (1848)
This species is accepted
The native range of this species is Ethiopia to NE. Tanzania. It is an annual and grows primarily in the seasonally dry tropical biome.

Descriptions

M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Morphology General Habit
Annual herb, 0.1–0.5 m tall; stem ± pubescent with short recurved hairs
Morphology Leaves
Leaves petiolate, glabrous to moderately hairy; blade ovate or narrowly ovate, up to15–35 × 10–24 mm, 1.5–2.5 times as long as broad, apex subacute or acute, margin serrate-crenate
Morphology Reproductive morphology Inflorescences
Verticillasters ± spaced; cymes 5–11-flowered, with up to 7 mm long peduncles; bracteoles stiff, ± patent, linear to subulate, 7–12 mm long; pedicels erect, 1–5 mm long
Morphology Reproductive morphology Fruits Fruiting calyx
Fruiting calyx 10-lobed, regular or almost so, 10–13 mm in fruit, with an annular vein near the limb, bearded in the mouth with up to 2 mm long hairs; lobes equal or subequal, subulate, ± spreading, 2–4 mm long
Morphology Reproductive morphology Flowers Corolla
Corolla 7–10 mm long; lower lip as long as or longer than upper lip
Morphology Reproductive morphology Flowers Gynoecium Style
Style branches short, unequal
Morphology Reproductive morphology Fruits
Nutlets trigonous-oblong, 2.4–3 × 1.2–1.5 mm, apex ± truncate and sparsely pubescent with minute stalked glands.
Distribution
S1, 2; Sudan, Ethiopia, Kenya, N Tanzania
Ecology
Altitude range 60–100 m.
[FSOM]

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. Leucas, G. Bramley. Flora of Tropical East Africa. 2009

Type
Types: Sudan, Kordofan, Arasch-Cool, Kotschy 111 (K!, syn.; BM!, BR, FT, G, UPS, W, isosyn.) & Kordofan, 1837/38, Kotschy 70 (K!, syn.; G, W, isosyn.)
Morphology General Habit
Annual, erect herb, unbranched or with occasional branching in upper half, 8–40(–70) cm high
Morphology Stem
Stems pubescent with short downward-pointing hairs and with sessile glands when young, becoming more glabrous and less glandular
Morphology Leaves
Leaves shortly petiolate; blades ovate, 1.5–4.2 × 0.9–2.4 cm, margin shallowly dentate, apex acute, base rounded, upper surface subglabrous (occasionally with scattered hairs), eglandular, lower surface laxly covered with short hairs, these more plentiful on venation, also densely covered with yellow sessile glands; petioles 4–14 mm long
Morphology Reproductive morphology Inflorescences
Inflorescence of 4–9 verticils spaced 22–50 mm apart; 12–16 flowers per verticil; pedicels 1.5–2.5 mm long, with short hairs, eglandular; bracteoles subulate, 8–9 mm long, with conspicuous spreading hairs ± 1 mm long and shorter appressed hairs
Morphology Reproductive morphology Flowers Calyx
Calyx funnel-shaped, slightly curved, tube 7–12 mm long at anthesis, not noticeably expanding in fruit, outer surface pubescent with short appressed hairs and scattered longer ones, also with yellow sessile glands, the inner edge with a fringe of erect white hairs, ± 1.5 mm long, the surface below this ± glabrous; throat ± symmetric, sometimes anterior lip slightly longer than posterior; lobes 10, subulate, somewhat reflexed, 2.5–4 mm long, with short appressed hairs and the occasional longer spreading hair
Morphology Reproductive morphology Flowers Corolla
Corolla with white hairs, 8–9.5 mm long; tube 3–6 mm long, the outer surface hairy and with yellow sessile glands in the upper half, the lower half ± glabrous, inner surface ± glabrous; posterior lip 2–2.5 mm long; anterior lip 1.5–3.5 mm long, inner surface with short hairs at the inner side of the lateral lobes, pointing towards the sinus between the lateral and centre lobe, outer surface pubescent and with red and yellow sessile glands
Morphology Reproductive morphology Fruits
Nutlets 2.5 × 1.5 mm, conspicuously warty, with scattered sessile glands
Ecology
Grassland, coastal or deciduous bushland, on sands and black cotton soils; 30–1100 m
Conservation
Least concern; widely distributed
Note
Easily recognisable due to its subulate bracteoles with conspicuous spreading hairs, and by its more or less symmetric calyx which has a prominent fringe of white hairs around the inner edge. In addition the pedicels are longer than is typical for most species of Leucas, and cause the cymes to appear quite loose.
Distribution
Range: Sudan, Ethiopia and Somalia Flora districts: K1 K2 K4 K7 T3
[FTEA]

Extinction risk predictions for the world's flowering plants to support their conservation (2024). Bachman, S.P., Brown, M.J.M., Leão, T.C.C., Lughadha, E.N., Walker, B.E. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.19592

Conservation
Predicted extinction risk: not threatened. Confidence: confident
[AERP]

Sources

  • Angiosperm Extinction Risk Predictions v1

    • Angiosperm Threat Predictions
    • http://creativecommons.org/licenses/by/4.0

  • Flora of Somalia

    • Flora of Somalia
    • http://creativecommons.org/licenses/by-nc-sa/3.0

  • 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 Vascular Plants 2026. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0

  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2026. Published on the Internet at http://www.ipni.org and https://powo.science.kew.org/
    • © Copyright 2023 International Plant Names Index and World Checklist of Vascular Plants. http://creativecommons.org/licenses/by/3.0