Begonia incudiformicarpa Ardi & D.C.Thomas, 2018

Ardi, Wisnu H., Chikmawati, Tatik, Witono, Joko R. & Thomas, Daniel C., 2018, A synopsis of Begonia (Begoniaceae) of Southeastern Sulawesi including four new species, Phytotaxa 381 (1), pp. 27-50 : 34-36

4. Begonia incudiformicarpa Ardi & D.C.Thomas , spec. nov. ( Figures 1 & 5 )

Sect. Jackia

This species resembles Begonia andersonii Kiew & Sang (2007: 204) , but differs from this species by its larger stipules (7–11 × 4–7 mm), longer petiole s (7–17 cm), broadly ovate to elliptic leaves with a crenate margin, larger tepals of the male flowers (outer tepals: 8–10 × 7–11; inner tepals: 7.5–9 × 2.5–4 mm) and female flowers (outer tepals: 5–7.5 × 5–9 mm; inner tepals: 4–6 × 1.5–4 mm). Begonia andersonii has stipules that are ca. 2 × 5 mm, the petioles are 2–10 cm long, the leaves are elliptic and have dentate margins, the outer male flower tepals are 6 × 4–6 mm, the inner male flower tepals are 4 × 1.2–2 mm, the outer female flower tepals are 3 × 3 mm, and the inner female flower tepals are 2 × 1 mm.

Type:— INDONESIA. Sulawesi, Southeast Sulawesi: Buton Island, Kakenauwe Village , 8 February 2017, W.H. Ardi WI 147 (holotype BO!; isotypes KRB!, SING!) .

Perennial, lithophytic, monoecious herb, up to ca. 10 cm tall. Stem rhizomatous, up to 10 cm long, internodes ca. 1–3 mm long. Leaves alternate; stipules persistent, triangular–ovate, 7–11 × 4–7 mm, asymmetric, margin entire and sparsely hairy, apex acute, midrib abaxially prominent, apex narrowed into bristle projecting up to 11 mm, hairy; petioles 7–17 cm long, terete, reddish, densely hairy, hairs up to 3 mm long; lamina basifixed, 4.5–12 × 4–8.8 cm, elliptic, asymmetric, coriaceous, margin crenate, ciliate and with recurved stiff teeth at the end of the veins, base rounded, lobes overlapping, apex rounded to obtuse, adaxially reddish–greenish or brownish–greenish, slightly prominent between veins, glabrous, abaxially red with green veins, hairy on the veins only; venation palmate, primary veins 7–9, actinodromus, secondary veins craspedodromus. Inflorescences: bisexual, protandrous, axillary, dichasial cymes, branching up to 2-times; peduncle 7.5–14.7 cm long, sparsely hairy to glabrescent; bracts anisophyllus, larger oblong 2.5–6 × 2–4 mm, smaller 1–3 × 1–1.5 mm, persistent; bracteoles minute, up to 4 × 1.5 mm, oblong, persistent. Male flowers: pedicels 5–13 mm long, glabrous, white tinged pink; tepals 4, 2 outer tepals suborbicular to orbicular, 9–10.5 × 7–11 mm, white tinged pink, slightly cordate at the base becoming truncate when open, margin entire, apex rounded, outer surface glabrous, 2 inner tepals elliptic, ca. 7–9 × 2.5–5 mm, base truncate, margin entire, apex obtuse, white; androecium yellow, symmetric, globose, on a ca. 1 mm long column; stamens ca. 61–65, free filaments up to ca. 0.5 mm long, fused at the base, anthers up to ca. 0.8–1 mm long, dehiscing through laterally positioned slits> 1 / 2 as long as the anthers. Female flowers: pedicel 6–11 mm long, glabrous, reddish; tepals 3, 2 outer broadly ovate 5–9 × 5–8 mm, slightly cordate at the base becoming truncate when open, margin entire, apex rounded, one inner tepal 4–6 × 1.5–4 mm, ovate to elliptic; ovary (excluding wings) 4.5–5 × 3.5–4 mm, ellipsoid, glabrous, green, locules 3, placentation axile, placentae entire, wings 3, subequal, reddish to red, base rounded or subcuneate, apex subtruncate, cuneate or convex-concave, widest point 4–8 mm (at the middle to subapically), style ca. 3 mm long, basally fused, 3– branched, each stylodium bifurcate in the stigmatic region, stigmatic surface a spirally twisted papillose band, orange.

Fruits: pedicels 9–17 mm long, recurved; seed-bearing part ovoid to ellipsoid, 5–7 × 4–6 mm (excluding the wing), wing shape as for ovary, widest point 5.5–6 mm (middle to subapically). Seeds barrel-shaped, ca. 0.3 mm long.

Distribution:— Indonesia; endemic to Sulawesi, Southeast Sulawesi, Buton Island, where it can be found in several localities (Kakenauwe Forest Reserve, Labuan Tobelo and Kabungka).

Habitat:— Limestone cliffs and coralline limestone rocks, in partial to dense shade; collected in a coconut plantation at the border of the Kaukenawe forest reserve, with Piper spec. and Ficus spec. , at ca. 5–180 m elevation.

Provisional IUCN conservation assessment:— Endangered EN B2ab(iii). The type specimens were collected from a coconut plantation, close to the border of Kakenauwe Forest Reserve, where the species is locally common. Further exploration might reveal that the distribution of the species extends into this protected area. Furthermore, it has a fairly wide distribution in central and north Buton in legally protected areas. However since the species has a small EOO (305 km 2) and AOO (12 km 2), is only known from a few collections, and some threats and antropogenic disturbances were observed (agriculture including coconut and cashew nut plantation), we consider the IUCN (2012) category of Endangered (EN) to be appropriate.

Etymology:— The specific epithet is a compound derived from “incudiformis” (Latin—anvilshaped) and “carpus” (Latin—fruit). It refers to the shape of the fruits which have wings with a pointed end. In side view, the fruit shape resembles the shape of an anvil.

Notes:— Begonia incudiformicarpa was first collected by Kjelberg from Kaboengka (Kabungka), Buton, in 1929, and subsequently by Mark Coode from Labuan Tobelo, North Buton, in 1989. Both collections have flowers and fruits, but since fruits were not preserved in alcohol, the placentation type remained uncertain. Placentation types have to been shown to be highly homoplasious in Asian Begonia ( Thomas et al. 2011) , but remain, in combination with various other flower and fruit characters as well as the presence or absence of tubers and rhizomes, a crucial character in sectional delimitation ( Thomas et al. 2011, Moonlight et al. 2018). The recent collection shows that B. incudiformicarpa belongs to Begonia section Jackia , as it exhibits typical characters of the section: a rhizomatous stem, protandrous inflorescences, a stamen column, and three-locular ovaries with entire placentae.

The presence of species of section Jackia on Buton, as well as Wawonii and the Sulawesi mainland (see B. iskandariana Ardi & D.C.Thomas , and B. tumburanoensis D.C.Thomas & Ardi below) represents a substantial eastwards extension of the known range of this section ( China: Guangxi, Jiangxi; Indonesia: Bali, Java, Kalimantan, Lesser Sunda Islands, Sumatra; Malaysia: Peninsular Malaysia, Sarawak; Vietnam; see Moonlight et al. [2018]).

Additional specimens examined:— INDONESIA. Sulawesi, Southeast Sulawesi: Buton Island, North Buton, Labuan Tobelo , 12 Nov. 1983, M.J.E. Coode 6206 ( BO, E, K, L) ; Indonesia, Buton Island, North Buton , Jismil Camp , Labuan Tobelo , upriver from Coode 6206, 13 Nov. 1983, M.J.E. Coode s.n. (L) ; Buton, Kaboengka , 15 Feb. 1929, G.K. Kjellberg 250 (S) .

Figures

FIGURE 1. Distribution map.A. Overview of Sulawesi. B. Distributions of B. aptera, B. johntania, B. mekonggensis, and B. ozotothrix.C. Distributions of B. balgooyi, B.flacca, B. matarombeoensis, and B. watuwilensis. D. Distributions of B.incudiformicarpa, B. iskandariana, and B. tumburanoensis. Specimen location information was georeferenced using the GeoNames geographical database at http://www. geonames.org/.

FIGURE 5. Begonia incudiformicarpa. A. Habit, plant in situ; scale bar: 5 cm. B. Habit, abaxial view; scale bar: 5 cm. C. Stipules; scale bar: 5 mm. D. Male flower; scale bar: 10 mm. E. Female flowers; scale bar: 10 mm. F. Female flowers, side view; scale bar: 5 mm. G. Fruit, side view; scale bar: 5 mm. H. Ovary, cross-section of middle part; scale bar: 3 mm. A–H from Ardi, W.H. 147 (Photos: W.H. Ardi).