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  1. Family: Fabaceae Lindl.
    1. Genus: Senegalia Raf.
      1. Senegalia nigrescens (Oliv.) P.J.H.Hurter

        This species is accepted, and its native range is Tanzania to S. Africa.

    [FTEA]

    Leguminosae, J. B. Gillett, R. M. Polhill & B. Verdcourt. Flora of Tropical East Africa. 1971

    Habit
    Trees 4–25 m. high; trunk usually ± beset with knobby prickles.
    Branches
    Young branchlets glabrous to sometimes pubescent.
    Stipules
    Stipules not spinescent.
    Prickles
    Prickles in pairs just below each node, hooked, blackish, persistent, 2.5–7 mm. long (on branchlets).
    Leaves
    Leaves:petiole glandular or not; rhachis glabrous to pubescent, sometimes with a gland between the top 1–2 pairs of pinnae; pinnae 2–4 pairs; leaflets 1–2 pairs, (8–) 10–26 (–50) mm. long, (6–) 7–22 (–45) mm. wide, obliquely obovate-orbicular to broadly obovate-elliptic, glabrous to sometimes pubescent, venose, subcoriaceous, apex rounded and often emarginate.
    Flowers
    Flowers white or cream, sessile, in ± aggregate or solitary spikes 1–9.5 cm. long on peduncles 0.6–2 cm. long; axis glabrous except for minute sessile glands, sometimes pubescent.
    Calyx
    Calyx 1.5–2 mm. long, glabrous.
    Corolla
    Corolla 2–2.5 mm. long, 5-lobed.
    Stamens
    Stamen-filaments 3.5–6 mm. long, free; anthers 0.1 mm. across, with a caducous gland.
    Ovary
    Ovary glabrous, very shortly stipitate.
    Fruits
    Pods (Fig. 14/9, p. 52) darkish brown, dehiscent, glabrous, oblong, straight, hardly venose, acuminate at apex, 7–14.5 cm. long, 1.5–2.4(–2.7) cm. wide.
    Seeds
    Seeds subcircular-lenticular, 12–13 mm. diam.; central areole large, 7–8 mm. long, 7 mm. wide, somewhat impressed.
    Habitat
    Deciduous bushland and probably also wooded grassland, especially in black-soil areas; 240–1160 m.
    Distribution
    southwards to Bechuanaland, the Transvaal and Zululand T1 T3 T4 T5 T6 T7 T8
    [ILDIS]

    International Legume Database and Information Service

    Conservation
    Not Threatened
    Ecology
    Africa: Tongaland-Pondoland regional transition zone; wooded grassland, Tongaland-Pondoland regional transition zone; woodland, Zambezian woodland
    Habit
    Perennial, Not climbing, Tree
    [FZ]

    Leguminosae, J.P.M. Brenan. Flora Zambesiaca 3:1. 1970

    Habit
    Tree 3-30 m. high; trunk usually ± beset with knobby prickles; young branchlets glabrous to sometimes pubescent.
    Stipules
    Stipules not spinescent.
    Prickles
    Prickles in pairs just below each node, hooked, blackish, persistent, 2·5-7 mm. long (on branchlets).
    Leaves
    Leaves: petiole glandular or not; rhachis glabrous to pubescent, sometimes with a gland between the top 1-2 pairs of pinnae; pinnae 2-4 pairs; leaflets normally 1-2 pairs, (6·5)10-35(50) x (5·3)7-30(49·8) mm., obliquely obovate-orbicular to broadly obovate-elliptic, glabrous to sometimes pubescent, venose, subcoriaceous, apex rounded and often emarginate.
    Flowers
    Flowers white or cream, sessile, in ± aggregate or solitary spikes 1-10(12) cm. long on peduncles 0·3-2·4 cm. long; axis glabrous except for minute sessile glands, or sometimes pubescent.
    Calyx
    Calyx 1·5-2 mm. long, glabrous.
    Corolla
    Corolla 2-2·5 mm. long, 5-lobed.
    Stamens
    Stamen-filaments 3·5-6 mm. long, free: anthers 0·1 mm. across, with a caducous gland.
    Ovary
    Ovary glabrous, very shortly stipitate.
    Fruits
    Pods darkish brown, dehiscent, 6·1-17·8 x 1·4-2·4(2·7) cm., glabrous, oblong, straight or nearly so, hardly venose, acuminate at the apex.
    Seeds
    Seeds 12-13 mm. in diam., subcircular-lenticular; central areole large, 6-8 x 6-8 mm., somewhat impressed.

    Images

    Distribution

    Native to:

    Angola, Botswana, Caprivi Strip, KwaZulu-Natal, Malawi, Mozambique, Namibia, Northern Provinces, Swaziland, Tanzania, Zambia, Zimbabwe

    Synonyms

    Common Names

    English
    Knob-thorn

    Other Data

    Senegalia nigrescens (Oliv.) P.J.H.Hurter appears in other Kew resources:

    Date Reference Identified As Barcode Type Status
    Mar 17, 2011 Zimba, N.B. [936], Zambia Acacia nigrescens K000724189
    de Winter, B. [4078], Namibia Acacia nigrescens K000489543
    Kirk, J. [s.n.], Malawi Acacia nigrescens K000244313 Unknown type material
    Kirk, J. [201], Mozambique Acacia nigrescens K000244314 Unknown type material
    Long, D.G. [668], Botswana Acacia nigrescens K000489541
    Long, D.G. [496], Botswana Acacia nigrescens K000489542
    Burtt Davy, J. [2452], South Africa Acacia nigrescens K000244379
    Lugard, E. F. [246], Botswana Acacia nigrescens K000244315 Unknown type material
    Biegel, H. [3865], Botswana Acacia nigrescens K000489540
    de Beer, J.S. [782], Botswana Acacia nigrescens K000489539

    Bibliography

    First published in D.J.Mabberley, Plant-book, ed. 3: 1021 (2008)

    Literature

    Kew Backbone Distributions

    • Figueiredo, E. & Smith, G.F. (2008). Plants of Angola Strelitzia 22: 1-279. National Botanical Institute, Pretoria.
    • Brenan, J.P.M. (1970). Flora Zambesiaca 3(1): 1-153. Royal Botanic Gardens, Kew.

    Sources

    Flora Zambesiaca
    Flora Zambesiaca
    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
    'The Herbarium Catalogue, Royal Botanic Gardens, Kew. Published on the Internet http://www.kew.org/herbcat [accessed on Day Month Year]'. Please enter the date on which you consulted the system.
    Digital Image © Board of Trustees, RBG Kew http://creativecommons.org/licenses/by/3.0/

    International Legume Database and Information Service
    International Legume Database and Information Service (ILDIS) V10.39 Nov 2011
    http://creativecommons.org/licenses/by/3.0

    Kew Backbone Distributions
    The International Plant Names Index and World Checklist of Selected Plant Families 2020. 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 2020. 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

    Kew Science Photographs
    Digital Image © Board of Trustees, RBG Kew http://creativecommons.org/licenses/by/3.0/

    Plants and People Africa
    Common Names from Plants and People Africa http://www.plantsandpeopleafrica.com/
    © Plants and People Africa http://www.plantsandpeopleafrica.com http://creativecommons.org/licenses/by/3.0/