1. Family: Rutaceae Juss.
    1. Genus: Zanthoxylum L.
      1. Zanthoxylum usambarense (Engl.) Kokwaro

        This species is accepted, and its native range is E. & S. Ethiopia to Rwanda.

    [FTEA]

    Rutaceae, J.O. Kokwaro (University of Nairobi). Flora of Tropical East Africa. 1982

    Habit
    A much-branched tree 8–14(–16) m. high; trunk without branches for several m., 22–35 cm. in diameter at the base, armed with conical woody prickle-bearing outgrowths 2–3 cm. long ending in sharp straight thorns 5–9 mm. long; bark conspicuously rough, with longitudinal ridges and furrows (as deep as 5 cm.), greyish brown but peeling yellow underneath; branches with sharp straight or slightly upcurved dark red prickles 6–12 mm. long; roots with yellow bark which (together with the bark) are heavily exploited for medicinal purposes.
    Leaves
    Leaves 10–24 cm. long; rhachis unarmed or with small straight or upcurved prickles; petiolule (0–)0.5–2 mm. long except on the terminal leaflets where it is up to 5 mm.; leaflets 2–8 pairs, usually subopposite to opposite, elliptic to elliptic-oblong, 2.2–8 cm. long, 1.5–3 cm. broad, acuminate or apiculate to almost obtuse at the apex, obtuse and slightly oblique to cuneate at the base, crenate, with distinct pellucid glands along the margin, coriaceous, glabrous; midrib occasionally aculeate beneath; lateral nerves 8–16 pairs.
    Inflorescences
    Inflorescence terminal much-branched corymbose panicles, 10–15 cm. long, 7–19 cm. broad, glabrous, with cymose clusters of flowers on pedicels 0–3 mm. long.
    Calyx
    Sepals 4, united at least at the base, ovate to elliptic, 1–1.5 mm. long, 1 mm. broad.
    Corolla
    Petals 4, elliptic to elliptic-oblong, 2–4.5 mm. long, 1.5–2.2 mm. broad, apiculate or obtuse, white to cream or greenish yellow.
    Male
    Male flowers:stamens 4; filaments 2–6 mm. long and variable in length in the same flower; anthers 1–2 mm. long; gynophore short, glabrous; vestigial pistils 2, up to 1.4 mm. long.
    Flowers
    Female flowers:staminodes absent; gynophore short; ovaries 2, partially united, 1–1.5 mm. long; styles 2, 0.8–1 mm. long; stigmas 2, often partially united. Male flowers:stamens 4; filaments 2–6 mm. long and variable in length in the same flower; anthers 1–2 mm. long; gynophore short, glabrous; vestigial pistils 2, up to 1.4 mm. long.
    Female
    Female flowers:staminodes absent; gynophore short; ovaries 2, partially united, 1–1.5 mm. long; styles 2, 0.8–1 mm. long; stigmas 2, often partially united.
    Fruits
    Fruit of paired subglobose follicles 8–10 mm. long, 6–7.5 mm. in diameter, mucronate, usually on a common stipe but individually sessile, one of the pair sometimes rudimentary, reddish green, glandular-foveolate, Seeds 5–7 mm. long, 4.5–5.5 mm. in diameter, dark blue-black and glossy.
    Habitat
    Upland forests; (1200–) 1600–2600 m.
    Distribution
    K1 K3 K4 K5 K6 K7 T1 T2 T3

    Distribution

    Native to:

    Ethiopia, Kenya, Rwanda, Tanzania

    Zanthoxylum usambarense (Engl.) Kokwaro appears in other Kew resources:

    First published in Kew Bull. 32: 798 (1978)

    Accepted by

    • Hedberg, I. & Edwards, S. (eds.) (1989 publ. 1990). Flora of Ethiopia and Eritrea 3: 1-659. The National Herbarium, Addis Ababa University, Ethiopia & The Department of Systematic Botany, Upps.
    • Troupin, G. (ed.) (1983). Flora du Rwanda 2: 1-603. Musee Royal de l'Afrique Centrale.
    • Kokwaro, J.O. (1982). Flora of Tropical East Africa, Rutaceae: 1-52.

    Literature

    Kew Backbone Distributions
    • Hedberg, I. & Edwards, S. (eds.) (1989 publ. 1990). Flora of Ethiopia and Eritrea 3: 1-659. The National Herbarium, Addis Ababa University, Ethiopia & The Department of Systematic Botany, Upps.
    • Troupin, G. (ed.) (1983). Flora du Rwanda 2: 1-603. Musee Royal de l'Afrique Centrale.
    Flora of Tropical East Africa
    • Kokwaro in Kew Bulletin 32:798 (1978).

    Sources

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