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


Girmansyah, D. 2013. Begonia ranaiensis (Begoniaceae), a new species from Mt Ranai, Natuna Island, Indonesia. Kew Bulletin 68: 179. DOI

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.
Endemic to Mt Ranai, NatunaBesar, Natuna Islands, Indonesia.
Terrestrial herb in tropical forest up to 700 m alt.
Morphology General Habit
Perennial, erect, monoecious herb, up to 50 cm tall
Morphology 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
Morphology Reproductive morphology 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
Morphology Reproductive morphology 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
Morphology Reproductive morphology Inflorescences
Inflorescence cymose, peduncle 0.6 – 1 cm long, male and female inflorescences separate on the same individual, each with two flowers, tepals pink
Morphology Reproductive morphology Seeds
Seeds barrel-shaped, 0.25 – 0.29 mm long, collar cells more than a half of the seed length
Morphology 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
Begonia ranaiensis is similar to B. angustilimba Merr. 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.
Type: Indonesia, Riau Archipelago, Natuna Islands, Great Natuna, Bünnemeijer 5907 (holotype BO!; isotype BO!).

Native to:


Begonia ranaiensis Girm. appears in other Kew resources:

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

Accepted by

  • Govaerts, R., Nic Lughadha, E., Black, N., Turner, R. & Paton, A. (2021). The World Checklist of Vascular Plants, a continuously updated resource for exploring global plant diversity. Scientific Data 8: 215.


Kew Bulletin

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  • Girmansyah, D. (2012). Two new species of Begonia (Begoniaceae) from Bukit Tigapuluj National Park, Riau, Sumatra. Reinwardtia 13(3): 229 – 233.
  • Girmansyah, D., Wiriadinata, H., Thomas, D. C. & Hoover, W. S. (2009). Two new species and one new subspecies of Begonia (Begoniaceae) from Southeast Sulawesi, Sulawesi, Indonesia. Reinwardtia, 13: 69 – 74.
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© Copyright 2017 World Checklist of Selected Plant Families.

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Kew Names and Taxonomic Backbone
The International Plant Names Index and World Checklist of Selected Plant Families 2021. Published on the Internet at and
© Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families.