Begonia comestibilis D.C.Thomas & Ardi in Edinburgh J. Bot. 68(2): 226. 2011

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Content

Begonia Section

  • Petermannia

Diagnosis

  • A ceteris speciebus Begoniae celebicis combinatione characterum foliorum peltatorum, inflorescentiis masculis valde compressis et alarum fructuum bene evolutarum differt. - Type: Indonesia, Sulawesi, Sulawesi Selatan, Lompobatang Mountains, close to Malino, Katemujotup waterfall, disturbed forest at margin of coffee plantation, 05°16'30.90S, 119°51'53.70E, 1030 m, 11 iv 2009, D.C. Thomas & W.H. Ardi 09-62 (holo E; iso BO, L).
    (Thomas, D.C., Ardi, W.H. & Hughes, M., Nine new species of Begonia (Begoniaceae) from South and West Sulawesi, Indonesia in Edinburgh Journal of Botany 68(2). 2011)

Description

  • Perennial, monoecious herb with erect stems, to c.80 cm tall, glabrous except for a sparse indumentum of microscopic, glandular hairs. Stems branched; internodes c.4-13 cm long, reddish.

    Leaves alternate, usually excentrically peltate, or sometimes both peltate leaves and leaves with basifixed lamina present; stipules caducous, 13-17 × 6-12 mm, elliptic to oblong, with an abaxially prominent midrib that projects up to c.4 mm at the apex; petioles 4-18 cm long, reddish; lamina 13-17.3 × 7.1-10.5 cm, very asymmetric, ovate to elliptic, leaf margin slightly sinuate close to the petiole (excentrically peltate leaves) or base cordate and lobes not overlapping (basifixed laminas), apex acuminate, margin dentate to serrate to bidentate or biserrate, teeth not bristle-pointed, adaxial surface mid green and abaxial surface pale green, coriaceous, primary veins 5-6, actinodromous, secondary veins craspedodromous.

    Inflorescences: protogynous; female inflorescences 2-flowered, usually positioned one node below the male inflorescences, peduncles c.1-1.5 mm long; male inflorescences usually distal to the female inflorescences, composed of 1-5 cymose subumbellate partial inflorescences, each with 1-3 strongly compressed monochasia with up to 7 flowers, peduncles 9-38 mm long.

    Male flowers: pedicels 15-31 mm long; tepals 2, white, 8-14 × 11-17 mm, broadly ovate to suborbicular, base slightly cordate, apex rounded; androecium of c.76-92 stamens, yellow, filaments up to c.2 mm long, slightly fused at the very base, anthers c.0.9-1.5 mm long, obovate to oblong, dehiscing through unilaterally positioned slits that are > 1/2 as long as the anther.

    Female flowers: pedicels 6-10 mm long; tepals 5, white with pinkish veins, subequal, 14-18 3 8-11 mm, obovate to elliptic; ovary ellipsoid, locules 3, placentation axile, placentae bilamellate, wings 3, triangular, subequal, base rounded to cuneate, apex rounded to subtruncate, widest subapically, style basally fused, 3-branched, each stylodium bifurcate in the stigmatic region, stigmatic surface a spirally twisted papillose band, yellow. Fruiting pedicels up to 1 cm long.

    Fruits semi-fleshy, ellipsoid, 17-26 × 6-10 mm (excluding the wings), indehiscent?, wing shape as for ovary, 11-16 mm wide at the widest point (at the apex); seeds ellipsoidal, c.0.35-0.4 mm long, collar cells c.1/2-2/3 of the length of the seed. (Thomas, D.C., Ardi, W.H. & Hughes, M., Nine new species of Begonia (Begoniaceae) from South and West Sulawesi, Indonesia in Edinburgh Journal of Botany 68(2). 2011)

Habitat

  • This is a rainforest floor species, observed on a steep slope at c.1020-1040 m above sea level.

Conservation

  • Proposed IUCN conservation category: Vulnerable (VU D2). The Lompobatang massif is densely populated, and the majority of forest below 1700 m is heavily disturbed or has been converted by logging and land clearance for settlements and agriculture. This also holds true for the area surrounding the forest patch in which Begonia comestibilis was collected. The known distribution of this species falls outside the Lompobatang Protected Forest (IUCN category VI). Although all available Begonia specimens from A, B, BM, BO, CEB, E, K, L, SING and WAG have been consulted, only two collections are known. Hence it must be assumed, at least until more intensive collecting on Sulawesi reveals otherwise, that this species has a very restricted extent of occurrence. Begonia comestibilis grows abundantly at the type locality, but because of the restricted distribution the population is likely to ¨be prone to the effects of human activities or stochastic events within a very short time period in an uncertain future¨ (IUCN, 2001). Given the pressures on the forests in this region, and the direct threat to the only known population by human activity (extensive coffee plantations, rice agriculture, human settlements), this species must be considered vulnerable. Close monitoring of the population might indicate an even higher threat category. (Thomas, D.C., Ardi, W.H. & Hughes, M., Nine new species of Begonia (Begoniaceae) from South and West Sulawesi, Indonesia in Edinburgh Journal of Botany 68(2). 2011)

Distribution

Asia-Tropical: Sulawesi (Sulawesi endemic)
Endemic to Indonesia, Sulawesi, South Sulawesi.
See 'Specimens' tab for map of point distribution data of georeferenced specimens.

Etymology

  • The specific epithet is derived from comestibilis (Latin - edible). The leaves of Begonia comestibilis, which is called Indokaciling in the Malay dialect of the local people, are locally used as a vegetable and either eaten raw for their sour and refreshing taste or as an ingredient for a sour sauce used for chicken dishes. (Thomas, D.C., Ardi, W.H. & Hughes, M., Nine new species of Begonia (Begoniaceae) from South and West Sulawesi, Indonesia in Edinburgh Journal of Botany 68(2). 2011)A
A. Thomas, D.C., Ardi, W.H. & Hughes, M., Nine new species of Begonia (Begoniaceae) from South and West Sulawesi, Indonesia in Edinburgh Journal of Botany 68(2). 2011

Notes

  • Begonia comestibilis belongs to a group of Sulawesi species which show either a fleshy, relatively thick pericarp and reduced wings (Begonia guttapila, B. vermeulenii, B. rieckei) or a semi-fleshy pericarp, often thick placenta lamellae and well-developed wings (B. comestibilis, B. sanguineopilosa, B. torajana). Numerous fruits and ovaries of Begonia comestibilis at various ontogenetic stages were observed in the field in April 2009, and none of the fruits showed any signs of dehiscence. Further observations later in the season are needed to confirm whether these fruits are indehiscent or whether they dehisce in the usual mode with lines of dehiscence along the bases of the wings. (Thomas, D.C., Ardi, W.H. & Hughes, M., Nine new species of Begonia (Begoniaceae) from South and West Sulawesi, Indonesia in Edinburgh Journal of Botany 68(2). 2011)

Molecular Systematics

  • GenBank

    see Thomas et al., 2012 (Thomas, D.C., Hughes, M., Phutthai, T., Ardi, W.H., Rajbhandary, S., Rubite, R., Twyford, A.D. & Richardson, J.E. 2012: West to east dispersal and subsequent rapid diversification of the mega-diverse genus Begonia (Begoniaceae) in the Malesian archipelago. – Journal of Biogeography 39: 98-113)

Specimens

  • Indonesia, Sulawesi, Sulawesi Selatan, Katemujotup waterfall, alt. 1030 m, 5°16'30.9"S, 119°51'53.7"E, strongly disturbed forest at margin of coffee plantation, 11.4.2009, Thomas, D.C. & Ardi, W.H. 09-62 (BO, E, L). Sulawesi, South Sulawesi: Malino, 10.10.1931, Rant, A. 421 (BO). (Thomas, D.C., Ardi, W.H. & Hughes, M., Nine new species of Begonia (Begoniaceae) from South and West Sulawesi, Indonesia in Edinburgh Journal of Botany 68(2). 2011)