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  1. Family: Urticaceae Juss.
    1. Genus: Pilea Lindl.
      1. Pilea usambarensis Engl.

        This species is accepted, and its native range is SE. Kenya and N. Malawi.

    [FZ]

    Urticaceae, I. Friis. Flora Zambesiaca 9:6. 1991

    Habit
    Erect or ascending, presumably perennial herbs, monoecious; stems up to 10(50) cm. tall, thin and juicy, prostrate or erect, unbranched or branched, sometimes profusely branched, glabrescent.
    Leaves
    Leaves of a pair subequal or one with a longer petiole than the other, 1–3(11) x 0.8–2.5(4.5) cm., variable in size and shape from subcircular to ovate, lanceolate or elongate; apex acuminate or rounded; base cuneate, rounded or truncate; margin coarsely dentate or serrate with 4–9(15) teeth on each half of lamina; lamina upper surface with scattered stiff hairs or glabrous, cystoliths linear, lower surface glabrous to puberulous with scattered hydathodes.
    Petiole
    Petiole (0.5)1–5.5 cm. long, glabrous.
    Stipules
    Stipules up to 2.5 mm. long, ovate to almost rim-like, with a rounded base.
    Inflorescences
    Inflorescences axillary, usually 2 together in upper leaf axils, usually the pair of the same sex; flowers in stalked heads or interrupted spikes with 2–3 glomerules along the axis. Male clusters up to 8(13) mm. in diam., male flowers on pedicels up to 3 mm. long, 3(4)-merous, with apiculate tepals. Female clusters up to 6 mm. in diam., female flowers on pedicels 1–2 mm. long, 3-merous, tepals with appendages as in the male flower, middle tepal lanceolate, up to 1.5 mm. long, lateral tepals shorter.
    Male
    Male clusters up to 8(13) mm. in diam., male flowers on pedicels up to 3 mm. long, 3(4)-merous, with apiculate tepals.
    Female
    Female clusters up to 6 mm. in diam., female flowers on pedicels 1–2 mm. long, 3-merous, tepals with appendages as in the male flower, middle tepal lanceolate, up to 1.5 mm. long, lateral tepals shorter.
    Fruits
    Achene compressed, ± narrowly ovoid, up to 1 mm. long, dull brown.
    [FTEA]

    Urticaceae, I. Friis University of Copenhagen, Denmark. Flora of Tropical East Africa. 1989

    Habit
    Perennial herb with prostrate and ascending stems, up to 0.4(–0.5) m. high.
    Stem
    Stems juicy, glabrous.
    Leaves
    Leaves of a pair subequal or one with longer petiole than the other; stipules short, persistent but insignificant, broadly triangular to almost rim-like, up to 0.8 mm. long, translucent, whitish or greenish; petiole 0.5–4 cm. long, glabrous or with a few hairs at connection with lamina; lamina very variable in size and shape, from almost circular or broadly ovate to lanceolate or elongate, 1–11 cm. long, 1–4.5 cm. wide, base truncate to broadly cuneate, margin serrate, with 3–15 teeth on each side, apex rounded, acute or acuminate; lateral nerves 3–11 pairs, basal pair reaching 2nd–4th tooth from the apex; glabrous on both sides, or rarely with scattered stiff hairs above and spreading hairs on the nerves below, upper surface with regularly scattered linear cystoliths, lower surface with scattered hydatodes.
    Inflorescences
    Inflorescences peduncular heads, usually 2 together in the upper leaf-axils, usually the 2 of a pair of the same sex; ♂ inflorescences globose cymose heads, 0.8–1.3 cm. in diameter, on peduncles 1.5–5.5 cm. long; ♀ inflorescences globose cymose heads, 0.4–0.6 cm. in diameter, on peduncles 0.8–1.4 cm. long, sometimes the inflorescence-axis branched 2–3 times below the primary head, so the inflorescence consists of up to 5 heads (rarely only 2, one above the other, as on an unbranched inflorescence-axis).
    Male
    Male flowers on pedicels 0.8–1.4 mm. long; perianth ± 1 mm. in diameter; perianth 3-merous, tepals with subapical appendage.
    Flowers
    Female flowers subsessile; perianth ± 1 mm. long, one perianth-segment ± 1 mm. long, with a subapical appendage up to 0.8 mm. long, the 2 lateral perianth-segments very short. Male flowers on pedicels 0.8–1.4 mm. long; perianth ± 1 mm. in diameter; perianth 3-merous, tepals with subapical appendage.
    Female
    Female flowers subsessile; perianth ± 1 mm. long, one perianth-segment ± 1 mm. long, with a subapical appendage up to 0.8 mm. long, the 2 lateral perianth-segments very short.
    Fruits
    Achene ovoid, compressed, ± 0.8 mm. long, brown.

    Images

    Distribution

    Native to:

    Kenya, Malawi, Tanzania, Zaïre

    Accepted Infraspecifics

    Other Data

    Pilea usambarensis Engl. appears in other Kew resources:

    Date Reference Identified As Barcode Type Status
    Verdcourt [207], Tanzania K000242920 neotype

    Bibliography

    First published in Abh. Königl. Akad. Wiss. Berlin 1894: 50 (1894)

    Accepted by

    • Launert, E. & Cope, G.V. (eds.) (1991). Flora Zambesiaca 9(6): 1-135. Royal Botanic Gardens, Kew.
    • Friis, I. (1989). Flora of Tropical East Africa, Urticaceae: 1-64.
    • Robyns, W. & al. (eds.) (1948-1963). Flore du Congo Belge et du Ruanda-Urundi 1-10.

    Literature

    Kew Backbone Distributions

    • Launert, E. & Cope, G.V. (eds.) (1991). Flora Zambesiaca 9(6): 1-135. Royal Botanic Gardens, Kew.
    • Robyns, W. & al. (eds.) (1948-1963). Flore du Congo Belge et du Ruanda-Urundi 1-10.

    Flora of Tropical East Africa

    • Hauman in Flore du Congo Belge et du Ruanda-Urundi, 1: 202 (1948).
    • Rendle in Flora of Tropical Africa 6(2): 275 (1917).
    • Engl., Die Pflanzenwelt Ost-Afrikas und der Nachbargebiete, Theile C: 163 (1895).

    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/

    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