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Begonia ranoposoensis in Taiwania 68(2): 180. 2023
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Diagnosis
- Begonia ranoposoensis vegetatively resembles Begonia vermeulenii Thomas because of the succulent, peltate leaves, but the male inflorescences are composed of up to 18 monochasial partial inflorescences, each with 4–12 flowers (vs composed of 1–3 cymose-subumbellate partial inflorescences composed of 2 compressed monochasia with up to 5 flowers), an androecium of 21–29 stamens (vs 35–44 stamens), the female flower pedicel is 1–4 mm long (vs 5–10 mm long), and the ovaries and fruit (dry capsules) have 3 well-developed wings (vs ovaries and fruit wingless; fruit fleshy and indehiscent). (Saleh, Muhammad F.R.M., Bandjolu, K.P. & Ardi, W.H. 2023: Begonia ranoposoensis (Begoniaceae), a new species from Sulawesi, Indonesia. – Taiwania 68(2): 180-184. http://doi.org/10.6165/tai.2023.68.180)
Description
- Perennial, monoecious herb, creeping to semi-erect,forming clumps, up to 50 cm tall. Stem brownish-red, swollen at the nodes, glabrous except for microscopic glandular hairs, internodes 2–6.7 cm long. Leaves alternate, excentrically peltate; stipules caducous, ovateto elliptic, slightly asymmetric, 6‒11 × 3–6 mm, midrib abaxially prominent, apex shortly cuspidate, cusp up to 4mm long, margin entire, brownish-red, translucent, glabrous; petioles (4.5–) 6.6–14 cm long, brownish-red, terete, glabrescent; lamina 8–20 × 3–11 cm, asymmetric, ovate to elliptic, apex acuminate, margin irregularly and distantly dentate or serrate, adaxial surface green and abaxial surface pale green, glabrous; venation palmate-pinnate, primary veins 5–7, actinodromous, secondary veins craspedodromous. Inflorescences: protogynous; female inflorescences basal to male inflorescences, 1 or2-flowered, peduncles 1–3 mm long; bracts ovate-lanceolate, 7–8 × 3–4 mm, midrib prominent, mucronate, mucro 1–2 mm long, pale red; male inflorescences racemose-cymose (a thyrse) composed of up to 18 partial inflorescences, each compressed subumbellate with 4–12flowers, peduncles 0.6–3.5 cm long, greenish-red; bracts ovate to lanceolate 4–6 × 2 mm, midrib prominent, projecting up to 1 mm long. Male flowers; pedicels 12–14 mm, pale green, glabrous; tepals 2, white or white tinged with pink, 6–11 × 6–12 mm, broadly ovate, base rounded, apex rounded-retuse, glabrous; androecium of21–29 stamens, yellow, filaments 0.5–1.1 mm long, fused at base, unequal, longer in the middle of the androecium, anthers c. 0.5 mm long, obovate, dehiscing through unilaterally positioned slits c. 1/2 as long as the anther, connective not projecting. Female flowers: pedicels 1–4mm long, greenish-red, glabrous; tepals 5, white or white tinged pink, unequal, the four larger outer 8–10 × 5–6 mm, elliptic-lanceolate, the smaller inner one 8–9 × 3–4 mm, elliptic-lanceolate, glabrous; ovary (excluding wings) 8–9 × 1.5–2.5 mm, cylindrical, pink or reddish-white, glabrous, locules 3, placentation axile and bilamellate, wings 3, rounded at the base, truncate or rounded at the apex, up to 6 mm at the widest point (apically); style basally fused, 3-branched, each stylodium bifurcate, stigmatic region spirally twisted and papillose, the style and stylodia pale yellow, stigma yellow. Fruits: peduncles 1.5–2 mm long; pedicels 1–4 mm long, greenish-red; seed-bearing part ellipsoid, 9–17 × 2.5–5mm (without wings), wings shape as for ovary, widest point at the apex, up to 7 mm. Seeds unknown. (Saleh, Muhammad F.R.M., Bandjolu, K.P. & Ardi, W.H. 2023: Begonia ranoposoensis (Begoniaceae), a new species from Sulawesi, Indonesia. – Taiwania 68(2): 180-184. http://doi.org/10.6165/tai.2023.68.180)
Habitat
- Growing on vertical limestone cliffs, cave entrance or the forest floor in lowland karst forest, at 300–500 m elevation. (Saleh, Muhammad F.R.M., Bandjolu, K.P. & Ardi, W.H. 2023: Begonia ranoposoensis (Begoniaceae), a new species from Sulawesi, Indonesia. – Taiwania 68(2): 180-184. http://doi.org/10.6165/tai.2023.68.180)
Conservation
- Endangered EN B2ab(iii).
This species is only known from a few collections, and some anthropogenic threats including agriculture and mining were observed near the collection localities. The type specimens were collected from lowland forests in a legally unprotected area near Poso Lake. Given the small EOO (687 km2) and AOO (24 km2), we consider the IUCN Red List Category (IUCN, 2019) of Endangered (EN) to be appropriate. (Saleh, Muhammad F.R.M., Bandjolu, K.P. & Ardi, W.H. 2023: Begonia ranoposoensis (Begoniaceae), a new species from Sulawesi, Indonesia. – Taiwania 68(2): 180-184. http://doi.org/10.6165/tai.2023.68.180)
Distribution
Indonesia: endemic to Sulawesi, Central Sulawesi Province (Poso Regency, Pamona Puselemba District, Torau Cave, Saluopa waterfall, Leboni) and South Sulawesi Province (Soroako, Karrebe) (Saleh, Muhammad F.R.M., Bandjolu, K.P. & Ardi, W.H. 2023: Begonia ranoposoensis (Begoniaceae), a new species from Sulawesi, Indonesia. – Taiwania 68(2): 180-184. http://doi.org/10.6165/tai.2023.68.180)
Etymology
- The specific epithet is derived from the local name of the locality where the species was found and collected - Rano Poso (Pamona Language): Poso Lake. (Saleh, Muhammad F.R.M., Bandjolu, K.P. & Ardi, W.H. 2023: Begonia ranoposoensis (Begoniaceae), a new species from Sulawesi, Indonesia. – Taiwania 68(2): 180-184. http://doi.org/10.6165/tai.2023.68.180)A
Notes
- Only a few Sulawesi species in Begonia section Petermannia have peltate leaves. Begonia vermeulenii (Thomas et al., 2011) shows peltate leaves, while both peltate and basifixed leaves can be found in B. varipeltata (Thomas and Hughes, 2008) and B. comestibilis (Thomas et al., 2011). Begonia ranoposoensis can be differentiated from these species by its inflorescence morphology, fruit morphology and multiple other characters as indicated in Table 1. (Saleh, Muhammad F.R.M., Bandjolu, K.P. & Ardi, W.H. 2023: Begonia ranoposoensis (Begoniaceae), a new species from Sulawesi, Indonesia. – Taiwania 68(2): 180-184. http://doi.org/10.6165/tai.2023.68.180)
Specimens
- INDONESIA. Sulawesi, Central Sulawesi: Poso Regency, Tentena, Saluopa Waterfall, 31 vii 2018, WH Ardi et al. WI 253 (BO, CEB, SING, FIPIA); Poso Regency, Tentena, Leboni, Tentena-Bada road, 1 viii 2018, WH Ardi et al. WI 256 (BO, SING, FIPIA); Poso Regency, Tentena, Tentena-Bada road, 1 viii 2018, WH Ardi et al. WI 274 (BO, SING, FIPIA); Poso Regency, Tentena, Danau Poso, 1 viii 2018, WH Ardi et al. WI 275 (BO, CEB, FIPIA). South Sulawesi: Sungai Bambalano, 20 km SW on road Soroako-Wasuponda-Malili, 26 vii 1979, de Vogel et al., 6005 (L, BO); Walambano village, Soroako, 17 vi 1979, E Hennipman 5885 (A, BO, K, L); Karebbe, 15 viii 1929, G Kjellberg 2107 (BO). (Saleh, Muhammad F.R.M., Bandjolu, K.P. & Ardi, W.H. 2023: Begonia ranoposoensis (Begoniaceae), a new species from Sulawesi, Indonesia. – Taiwania 68(2): 180-184. http://doi.org/10.6165/tai.2023.68.180)