Ziziphus horsfieldii Miq.

First published in Fl. Ned. Ind. 1(1): 643 (1856)
This species is accepted
The native range of this species is Andaman & Nicobar Islands, W. Malesia to Philippines (Palawan, Mindoro). It is a liana and grows primarily in the wet tropical biome.

Descriptions

Cahen, D., Rickenback, J. & Utteridge, T.M.A. A revision of Ziziphus (Rhamnaceae) in Borneo. Kew Bull 76, 767–804 (2021). DOI: https://doi.org/10.1007/s12225-021-09970-3

Type
Indonesia, Java, 1802 – 1818, Horsfield s.n. (lectotype, selected here: K [K000723025]).
Morphology General Habit
Woody climber to at least 30 m long; girth to at least 10 cm in diam., spiny
Morphology Branches
Branchlets terete, with longitudinal striations and conspicuous, raised lenticels, hairs sparse, c. 0.5 mm long mixed with shorter hairs ˂ 0.1 mm long, mostly appressed-antrorse, reddish to whitish
Morphology Leaves Stipules
Stipules modified into spines, single, recurved, c. 2.5 mm long, subglabrous
Morphology Leaves
Leaves weakly discolorous, drying greenish-brown, blade asymmetric, (lanceolate –) narrow ovate (– ovate), 3.5 – 10.0 × 1.2 – 4.5 cm, chartaceous to subcoriaceous, apex attenuate to acuminate, base cuneate to subcordate, usually clearly oblique, margins finely denticulate, c. 100 serrations on either side, each serration topped by a protruding callosity that dries darker than the lamina, c. 0.1 mm long; primary veins 3, impressed adaxially, raised abaxially, hairs sparse along primary veins on either side of lamina, often more densely adaxially, hairs c. 0.2 mm long; strong marginal veins coming off the outside of the two outer main veins c. 6 on either side, rarely < 5, ascending and gradually diminishing, not forming conspicuous loops near margin¸ no clear intramarginal vein running along the leaf margin present, angle of divergence with outer main veins c. 45°; transverse veins between the main veins weak but discernible, especially adaxially, coming off midrib at c. 90°, barely raised (not readily felt by touch), spaced by c. 1 mm from each other, more often slightly zigzagging than straight; higher order reticulations barely discernible; lamina subglabrous; domatia present in the axils at the base of the 3 main veins and at the junction between the marginal veins and the outer main veins, pocket-like and often with tufts of hairs, swelling often visible adaxially just above junction between 3 main veins; petiole slightly dorsiventrally flattened, c. 7 mm long, hairs dense, indumentum extending to widened base of main veins adaxially
Morphology Reproductive morphology Inflorescences
Inflorescence of axillary pedunculate cymes, < ½ as long as subtending leaves, c. 12 flowers in each cyme, cymes loose dichasia with usually peduncle and first 2 branches clearly elongate and next 4 branches short but distinct; peduncles dorsiventrally flattened (5 –) 10 (– 15) mm long, hairs abundant, mostly < 0.1 mm long; pedicels c. 2 mm long, straight to slightly curved; bracteoles entire, narrowly triangular, c. 1 mm long, hairy
Morphology Reproductive morphology Flowers
Flower faintly scented; hypanthium densely hairy on the outer surface, hairs ˂ 0.1 mm long, appressed-antrorse, greyish; sepals triangular, c. 1.2 mm long, pale greenish when fresh, glabrous and keeled adaxially; petals clawed, c. 1 mm long, obcordate, white; stamen filaments flat, subulate, c. 0.7 mm long, anthers c. 0.3 mm long, enclosed by petals; nectary disk yellow, pentagonal, 10-pitted, glabrous, annulus surrounding ovary barely raised; style arms 2, free for c. 1 mm, glabrous; ovary partially immersed, hairs dense
Morphology Reproductive morphology Fruits
Fruit a drupe, ripening yellowish-green, (0.9 –) 1.1 (– 1.5) × (0.7 –) 1.1 (– 1.5) cm, obovoid [wider towards apex], indumentum dense, hairs drying reddish, < 0.1 mm long; fruiting pedicels c. 5 ×1 mm; hypanthium remains annular at base of fruit.
Distribution
Brunei, Indonesia (Java, Kalimantan, Sumatra), Malaysia (Malay Peninsula, Sabah, Sarawak), Philippines (Mindoro, Palawan), Singapore.
Ecology
Borneo lowland rain forests; alt. 30 – 520 m.
Conservation
Least Concern (LC). Ziziphus horsfieldii is widely distributed in western Malesia and extends to the Philippines. It does not appear to be threatened. In Borneo, it could be declining and severely fragmented given recent widespread destruction of rainforests but was collected in the following protected areas in Sabah: Bidu-Bidu Protection Forest Reserve (IUCN Category Ia), Klias Protection Forest Reserve (IUCN Category not reported) and SG. Kinabatangan Valley Bird Sanctuary (IUCN Category not reported).
Phenology
Collected in flower in April, June, Oct. and Dec.; collected in fruit in March, June – Oct. and Dec.
Vernacular
Kanggomsopuan (Sandakan, fide Bousi et al. SAN 124340); Kuku menaul (Iban, fide Luang S.23451); UnakMenaul (Iban, fide Wong WKM 1281).
[KBu]

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]

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: threatened. Confidence: confident
[AERP]

Sources

  • Angiosperm Extinction Risk Predictions v1

    • Angiosperm Threat Predictions
    • http://creativecommons.org/licenses/by/4.0
  • 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 2024. 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 Bulletin

    • Kew Bulletin
    • http://creativecommons.org/licenses/by-nc-sa/3.0
  • Kew Names and Taxonomic Backbone

    • The International Plant Names Index and World Checklist of Vascular Plants 2024. 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