1. Family: Begoniaceae C.Agardh
    1. Genus: Begonia L.
      1. Begonia ranaiensis Girm.

        This species is accepted, and its native range is Borneo.

    [KBu]

    Girmansyah, D. 2013. Begonia ranaiensis (Begoniaceae), a new species from Mt Ranai, Natuna Island, Indonesia. Kew Bulletin 68: 179. DOI https://doi.org/10.1007/s12225-012-9428-7

    Type
    Type: Indonesia, Riau Archipelago, Natuna Islands, Great Natuna, Bünnemeijer 5907 (holotype BO!; isotype BO!).
    Habit
    Perennial, erect, monoecious herb, up to 50 cm tall
    Stem
    Stem upright; base repent, becoming woody, rooting at the nodes; internodes 1 – 8 cm apart, shorter nearer the apex, with dense short hairs near to the apex of the stem, becoming glabrous with age near the base; stipules large, persistent, 1.5 – 2 × 0.8 – 1 cm, boat-shaped when young and elongate triangular when adult, with scattered short hairs along the dorsal midvein, with a hair-like appendage at the apex
    Leaves
    Leaves alternate; petioles 0.5 – 1.3 cm long, sparsely to densely hairy; lamina 5 – 13 × 1.5 – 4.5 cm, asymmetric, ovate to elliptic, base unequal, cuneate to rounded, one side extending 2 – 3 mm further down the petiole than the other, broad side 1 – 3 cm wide, narrow side 1 – 1.5 cm wide, apex acute to acuminate, margin biserrate with minute hairs at the end of each tooth, upper surface glabrous, dark olive green and lower wine red with scattered short hairs on the veins, venation pinnate, 3 – 5 pairs, two pairs nearest the base arising opposite, remaining pairs alternate
    Inflorescences
    Inflorescence cymose, peduncle 0.6 – 1 cm long, male and female inflorescences separate on the same individual, each with two flowers, tepals pink
    Flowers
    Male flowers: pedicels 0.8 – 1 cm long, glabrous; tepals 2, white, 0.8 – 1 × 0.6 – 0.8 cm, obovate, glabrous; androecium c. 3 mm long, globose, stamens c. 20, filaments c. 1 mm long, fused at the base, anthers c. 2 mm long, oblong, dehiscing through unilateral slits c. ½ as long as anther Female flowers: pedicels c. 0.6 cm long; tepals 3, unequal, outer two ovate, 1.3 × 0.8 cm, inner one elliptic 1 × 0.7 cm; ovary capsule c. 1.2 × 0.8 cm, oval, locules 2, placentation axile, (placentae unknown); wings 2, equal, rounded at the apex, 2 mm wide; stigmas 2, style pale yellow, Y-shaped, 2.5 mm long
    Fruits
    Fruit: pedicel glabrous, 0.6 cm long; capsule oval, 1.3 × 0.8 cm, with 2 equal wings, wings 3 mm wide at the widest point, thinly fibrous, 2.5 – 4 mm wide, splitting between the locules and wings
    Seeds
    Seeds barrel-shaped, 0.25 – 0.29 mm long, collar cells more than a half of the seed length
    Note
    Begonia ranaiensis is similar to B. angustilimbaMerr. but distinguished by having ovate leaves, narrowly triangular stipules and fruits with two equal wings. There is only one fruit available for examination, and it has two wings. This is an unusual character for Begonia sect. Petermannia, and whether this is a constant or variable character (as in B. amphioxus Sands (1990); Kiew (2001)) needs further investigation. B. ranaiensis is most similar to B. angustilimba from Sandakan, North Borneo, but is distinct from this species in stem, stipule and leaf characters. B. ranaiensis has glabrous or short-haired stems, ovate to elliptic leaves without minute hairs at the end of the margin serrations and boat-shaped stipules; B. angustilimba has stems which are glabrous at the base but long-haired near the apex, elongate-oblong leaves, with minute hairs at end of the margin serrations, and triangular stipules. The species epithet is derived from the name of Mt Ranai.
    Distribution
    Endemic to Mt Ranai, NatunaBesar, Natuna Islands, Indonesia.
    Ecology
    Terrestrial herb in tropical forest up to 700 m alt.
    Conservation
    Satellite images dated September 2006 show intact forest at altitudes of above 150 m on GunungRanai, and hence suitable primary forest habitat for Begonia ranaiensis. However there is danger of encroachment of small-scale agriculture on the mountain, and the current status of the area as protection forest rather than national park means there is a ‘plausible future threat that could drive the taxon to CR or EX in a very short time’ (IUCN Standards & Petitions Subcommittee 2010). As the taxon is endemic to Mt Ranai and has an area of occupancy of less than 20 km2, an IUCN category of Vulnerable (VU D2) is appropriate.

    Distribution

    Begonia ranaiensis Girm. appears in other Kew resources:

    First published in Kew Bull. 68: 179 (2012)

    Literature

    Kew Bulletin
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    Sources

    Kew Backbone Distributions
    The International Plant Names Index and World Checklist of Selected Plant Families 2019. 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 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 Selected Plant Families 2019. 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