Begonia iskandariana 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 : 37-39

5. Begonia iskandariana Ardi & D.C. Thomas , spec. nov. ( Figure 1 & 6 )

Sect. Jackia

The inflorescence and habit of B. iskandariana most closely resembles that of B. incudiformicarpa from Buton Island, but it has a sparse indumentum on the petioles (vs densely hairy); smaller stipules (4–7 × 4.5–5 mm) with shorter appendage (up to 3 mm long) (vs 7–11 × 4–7 mm, appendage 7–11 mm long); inflorescences with small and deciduous bracts ca. 1 × 0.5 mm (vs bracts 2.5–6 × 2–4 mm, persistent); larger female flower tepals (outer 10–11 × 9.5–11 mm and inner 8.5–10 × 3.5–4 mm vs outer 5–7.5 × 5–9 mm and inner 4–6 × 1.5–4 mm), and the fruit wings are not pointed.

Type:— INDONESIA, Southeast Sulawesi: Wawonii Island , 23 February 2017, W.H. Ardi WI 184, (holotype BO!; isotypes KRB!, SING!) .

Perennial, lithophytic, monoecious herb, up to 15 cm tall. Stem rhizomatous, up to 4 cm long, internodes strongly compressed, ca. 1–3 mm long. Leaves alternate; stipules persistent, ovate, 4–7 × 4.5–5 mm, asymmetric, midrib abaxially prominent, apex narrowed into a bristle projecting up to 3 mm, hairy; petiole s 4–16.5 cm long, greenish to reddish, terete, sparsely hairy, hairs ca. 1 mm long, denser and woolly on the young petioles; lamina basifixed, 4.5–10 × 3.5–9 cm, suborbicular to broadly ovate, coriaceous, margin crenate to subentire and ciliate, with recurved stiff teeth at the end of the veins, base cordate and lobes overlapping, apex rounded to obtuse, adaxially green, flat, glabrous, abaxially pale green with sparse hairs on the veins only; venation palmate, primary veins 6–8, actinodromus, secondary veins craspedodromus. Inflorescences: bisexual, protandrous, axillary, dichasial cymes, branching 2-times; peduncle s 2.5 –10 cm long, glabrous; bracts ca. 1 × 0.5 mm, elliptic, persistent. Male flowers: pedicel 5–13 mm long, glabrous; tepals 4, unequal, white tinged pink, 2 outer tepals 7.5–11.5 × 7–10.5 mm, suborbicular to elliptic, glabrous, slightly cordate at the base becoming truncate when open, margin entire, apex rounded, outer surface glabrous; inner tepals 5.5–10 × 3.5–6 mm, obovate, margin entire, base cuneate, apex rounded to slightly emarginate; androecium yellow, symmetric, globose, on a ca. 1 mm long column; stamens ca. 42, free filaments up to ca. 0.5 mm long, fused at the base, anthers up to ca. 0.5–0.8 mm long, dehiscing through laterally positioned slits> ½ as long as the anthers. Female flowers: pedicels 11–13.5 mm long; tepals 3, unequal, pale pink, 2 outer tepals 10–11 × 9.5–11 mm, elliptic to suborbicular, slightly cordate at the base becoming truncate when open, margin entire, apex obtuse, one inner tepal ca. 8.5–10 × 3.5–4 mm, elliptic, base cuneate, margin entire, apex rounded; ovary (excluding wings) 5.5–6.5 × 5–5.5 mm, ellipsoid, reddish, glabrous, wings 3, subequal, base rounded, apex rounded to subtruncate, widest point (at the middle of the ovary or subapically) up to 6 mm, style ca. 2–2.5 mm long, basally fused, 3-branched, each stylodium bifurcate in the stigmatic region, stigmatic surface a spirally twisted papillose band, orange. Fruits: peduncles of infructescence 5.5–12.5 cm; pedicels 10–15 mm long, recurved; seed-bearing part globoid, 4.5–7 × 4–6.5 mm (excluding the wings), wings 3, subequal, shape as in ovary, widest point (at the middle or subapically) up to 7 mm. Seeds barrel-shaped, 0.2–0.3 mm long.

Distribution:— Indonesia; endemic to Sulawesi, Southeast Sulawesi (Wawonii Island and Kendari).

Habitat:— Limestone cliffs and stalactites at cave entrances at ca. 0–200 m elevation.

Etymology:— The specific epithet is selected to honour and commemorate the former Chairman of the Indonesian Institute of Sciences (Lembaga Ilmu Pengetahuan Indonesia —LIPI), Prof. Dr. Iskandar Zulkarnain (1959–2017).

Notes:— Begonia iskandariana is morphologically similar to B. incudiformicarpa from Buton (see diagnosis above) and B. tumburanoensis from Wawonii Island. A morphological comparison of B. iskandariana and these two species is presented in Table 1.

Provisional IUCN conservation assessment:— Critically Endangered CR B2ab(iii).This species is only known from a few collections in Southeast Sulawesi (on the mainland near Kendari and on Wawonii island), and the recent expedition could find only two small populations in forest remnants sourrounded by plantations (coconut, cacao and cashew nut). Furthermore, the known localities and the forests on the island are not gazetted as protected areas. In combination with very small EOO (ca. 0.3 km 2) and AOO, this warrants a Critically Endangered (Cr) status ( IUCN 2012).

Additional specimens examined:— INDONESIA. Sulawesi, Southeast Sulawesi: Kendari , 1874, O. Beccari HB4499 ( FI) ; Kendari , 28 Feb. 1929, G.K. Kjellberg 558 (S) ; Kendari , 9 Apr. 1920, G.K. Kjellberg 1218 (S) ; Wawonii island, Labeau cave , 24 Feb. 2017, W.H. Ardi WI 185 ( BO, KRB, SING) .

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 6. Begonia iskandariana. A. Habit, plant in situ; scale bar: 5 cm. B. Male flowers; scale bar: 10 mm. C. Female flower; scale bar: 5 mm. D. Female flower, side view; scale bar: 5 mm. E. Mature fruit; scale bar: 5 mm. F Ovary, cross-section of middle part; scale bar: 3 mm.A–F from Ardi, W.H. 185 (Photos: W.H. Ardi).