Begonia siccacaudata Doorenbos (2000: 400)

Thomas, Daniel C. & Ardi, Wisnu H., 2020, Synopsis of Begonia (Begoniaceae) of southwest Sulawesi and the Selayar Islands, Indonesia, including one new species, Phytotaxa 437 (2), pp. 73-96 : 91-93

13. Begonia siccacaudata Doorenbos (2000: 400) ( Fig. 1 & 7 )

Sect. Petermannia

Type:— INDONESIA. Sulawesi, South Sulawesi: Bantimurung Waterfalls, alt. 60 m, J.J. Wieringa 1902 (holo WAG!, iso L!).

Additional literature:— Thomas et al. (2011: 251) [identification key]; Hughes et al. (2018: 285) [photo plate].

Description:— Perennial, tuberous-rhizomatous herb to ca. 15 cm tall; glabrous except for microscopic glandular trichomes and bristle-pointed teeth of the leaf margin, or with sparse indumentum of white hairs up to ca. 1 mm long on adaxial leaf lamina veins and upper petioles. Stem composed of multiple tuberous units, each up to 3 × 1.1 cm, leaves and inflorescences arising from very short stems (to 5 mm long) from the tuberous units, glabrous. Leaves alternate; stipules persistent, ca. 5‒15 × 2‒4 mm, narrowly obovate, with an abaxially prominent midrib, apex narrowed into bristle up to 2 mm long, glabrous; petioles 4.8–10.5 cm long, glabrous or sometimes sparsely hairy in apical part, red or pale green; lamina basifixed, 5–13 × 3–10.4 cm, ovate, asymmetrical to symmetrical, base cordate, basal lobes not overlapping, apex acute to shortly acuminate, margin denticulate, serrulate, to distantly dentate, teeth bristle-pointed, adaxial surface dark green, sometimes variegated with rows of white spots, abaxial surface pale green to reddish, glabrous or with sparse indumentum on the veins; venation palmate-pinnate, primary veins 5–6, actinodromous, secondary veins craspedodromous. Inflorescences: protogynous; female flowers solitary, peduncle 1‒2 mm long, glabrous, bracts semi-persistent, 4−11 × 1.5−7 mm, elliptic, glabrescent; male inflorescences racemose-cymose composed of 2‒10 subumbellate partial inflorescences, each a compressed monochasium with 3‒5 flowers, peduncle of male partial inflorescence 6−36 mm long, hairy, bracts persistent, to 7−10 × 1.8−2 mm at the base of the inflorescence, narrowly ovate, abaxially hairy. Male flowers: pedicels 8–28 mm long, glabrous; tepals 2, white or pale pink, 8–11 × 11–12 mm, broadly ovate, base slightly cordate or convex, apex rounded, glabrous; androecium of ca. 20‒40 stamens, yellow, filaments ca. 0.5−1 mm long, fused into a short but distinct column up to ca. 1 mm long at the base, anthers ca. 0.8−1.2 mm long, obovate or elliptic, dehiscing through unilaterally positioned slits that are <½ as long as the anthers. Female flowers: pedicels 13−33 mm long, glabrous; tepals 5, white or pink, unequal to subequal, larger 11–14 × 7–9 mm, ovate to elliptic, smallest one 9−11 × 4−6 mm, obovate or narrowly elliptic, outer surface glabrous; ovary 5–10 × 5–8 mm (excluding the wings), elliptic, wings 3, equal, base rounded to cuneate, apex truncate, subtruncate, cuneate or convex, widest point up to 7 mm (middle to subapically), glabrous, locules 3, placentation axile, placentae bilamellate; style up to ca. 4.5 mm long, basally fused, 3–branched, each stylodium bifurcate in the stigmatic region, stigmatic surface a spirally twisted papillose band, stylodia yellowish, stigma orange. Fruit: dry capsule; peduncles to 2 mm long; pedicels to 45 mm long, glabrous to hairy; seed-bearing part 8−10 × 5−8 mm (excluding the wings), ellipsoid, wing shape as for ovary, glabrous. Seeds barrel-shaped, ca. 0.2−0.3 mm long.

Distribution: — Indonesia; endemic to Sulawesi: South Sulawesi (Bantimurung-Bulusaraung National Park, Karaenta Forest Reserve, Tanete Riaja) ( Fig. 1D ).

Habitat:— Limestone cliff walls, cave entrances, limestone boulders, mainly in lowland rainforests at 20 to 200 m elevation.

Provisional IUCN conservation assessment: — Vulnerable (VU) B1ab(iii),B2ab(iii). This species is a limestone endemic known only from southwest Sulawesi. Most of the collection localities fall within the legal protection of the Bantimurung-Bulusaraung National Park. The number of known locations and the associated EOO (ca. 892 km 2) and AOO are still very limited, however, and some suitable limestone hills in the wider area are surrounded by agricultural land resulting in strongly degraded vegetation, or are used as limestone quarries or for tourism and recreation.Therefore, we assess this species as Vulnerable.

Additional specimens examined: — INDONESIA. Sulawesi, South Sulawesi: Maros , 17 Feb. 1925, Smith 006 (K) ; Bantimurung, near Makassar , 20 May 1929, A. Rant 48 ( BO) ; Celebes zuid, Bantimoeroeng and vicinity, 20 Feb. 1938, P. Buwalda 3702, 3759 ( BO) ; Bantimurung Waterfalls , 20 June 1929, A. Rant 48 (L) ; Maros, Bantimurung Park , 20 Feb. 1938, P.J. Eyma 3702 ( BO, L) ; Maros, Bantimurung Park , 20 Feb. 1938, P.J. Eyma 3759 ( BO, L) ; Maros, Bantimurung Park , 13 Apr. 1975, W. Meijer 9125 (L) ; Maros, Bantimurung Park , 12 Feb. 1977, E. Widjaja 130 ( BO) ; Karaenta Nature Reserve , 16 Feb. 1981, H. Johansson et al. 8 (L) ; Karaenta Nature Reserve , 17 Feb. 1981, H. Johansson et al. 24 (L) ; Maros, about 3 km north Leangleang, at Gunung Kamaseh , 14 June 1986, S.C. Chin 3538 (L) ; Bantimoeroeng , 3 Feb. 1998, W.S. Hoover & H. Wiriadinata 881 ( BO) ; Bantimurung Waterfalls , Nov. 1998, J. van Veldhuizen s.n. ( WAG) ; Bantimurung National Park, Leang-Leang cave , 10 Apr. 2009, D.C. Thomas & W.H. Ardi 09-60 ( BO, E) ; Bantimurung National Park, close to Bantimurung waterfall, 15 Apr. 2009, D.C. Thomas & W.H. Ardi 09-75 ( BO, E) ; Maros District, Bantimurung subdistrict, Patunuang Asue Village , along Biseang Labboro bridge, 22 June 2010, E.A. Widjaya, EAW 9013 ( BO) ; Biringkassi Village, Pangkep , 2 Nov. 2018, W.H. Ardi 321 ( BO, KRB, SING) ; Tanete Riaja, Barru , 12 Nov. 2018, W.H. Ardi 359 ( BO, KRB, SING) .

Figures

FIGURE 1. Distribution maps of Begonia species occurring on the southwestern arm of Sulawesi or the Selayar Islands (georeferenced specimen data from major collections [B, BO, E, K, KRB, L, SING], the Begonia Resource Center [Hughes et al. 2015a], as well as some additional confirmed observations). Grey lines indicate 1° graticules.

FIGURE 7. Begonia siccacaudata. A: Cavemouth limestone habitat and growth habit. B: Stipule, short stem arising from rhizome, scale bar = 10 mm. C: Tuberous rhizome bearing young fruit; scale bar = 4 cm. D: Rhizome, longitudinal section of tuberous rhizome units; scale bar = 2 cm. E: Male inflorescence; scale bar = 10 mm. F: Male flower, front view; scale bar = 10 mm. G: Female flower, front view; scale bar = 12 mm. H: Female flower, side view; scale bar = 10 mm. I: Ovary cross-section, bilamellate placentation, scale bar = 3 mm. J: Fruit, side view; scale bar = 4 mm. A-F, I, J: Thomas & W.H. Ardi 09-60; G-H: Thomas & W.H. Ardi 09-75. Photos: D.C. Thomas.