Begonia stilpnophylla D.C.Thomas & Ardi, 2023

Thomas, Daniel, Ardi, Wisnu, Santana, Fernando, Pinto, Pedro, Loke, Frances Wei, Martins, Natalino Babo & Conaboy, Nathan, 2023, A NEW SPECIES OF BEGONIA (BEGONIACEAE) FROM INDONESIA AND TIMOR-LESTE, Edinburgh Journal of Botany 80 (1973), pp. 1-8 : 3-7

Begonia stilpnophylla D.C.Thomas & Ardi , sp. nov. [Section Jackia ]

This species is morphologically similar to Begonia pseudomuricata Girm. from Bali but differs by its more strongly compressed rhizome internodes (2–5 mm vs c. 10 mm long), glabrous petioles (vs sparsely to moderately densely hairy), smaller tepals of the male flowers (outer 10–11 × 8–9 mm, inner 12–14 × 6 mm vs outer 12–15 × 11–12 mm, inner 15–19 × 7 mm) and female flowers (outer 7–8 × 7–8 mm, inner 5 × 2–4 mm vs outer 10–11 × 9–10 mm, inner 9–10 × 3–4 mm). – Type : Timor-Leste, Viqueque Municipality , Loihuno , S of Loihuno waterfall, 8°47′10.501′′S, 126°22′49.624′′E, 257 m elevation, D. C. Thomas 3494, 29 viii 2022 (holotype SING, isotype E). Figure 1 .

Acaulescent, rhizomatous, perennial herb, to 38 cm tall. Rhizome to 11 cm long, with strongly compressed internodes, 2–5 mm long. Leaves alternate; stipules ovate-triangular, 18–25 × 10–12 mm, apex narrowed into a bristle up to 16 mm long, glabrous except for the hairy apical bristle, persistent; petiole 4.8–12.8 cm, glabrous, green to reddish; lamina basifixed, asymmetrical, 5.8–17.5 × 3.9–12.2 cm, ovate to elliptic, base cordate, basal lobes overlapping, apex acute to acuminate, adaxial surface green and with pale green veins, glabrous, abaxial surface pale green to greenish-reddish, paler light green along the veins, glossy, glabrous, margin sinuate, repand or shallowly lobed, distantly toothed, teeth often reflexed, sometimes with bristle at apex, margin sometimes distantly ciliate; venation palmate with 5 or 6 primary veins, secondary veins craspedodromous. Inflorescence protandrous, axillary, dichasial-cymose, few- to many-flowered, 8–36 cm long; peduncle 5.8–18.5 cm long; bracts narrowly ovate, narrowly elliptic to narrowly obovate, caducous,

to c.2 × 1 mm, smaller in the distal part of the inflorescence, sometimes the basal bracts with a few hairs abaxially. Male flower pedicel 8–9 mm long, white to pinkish; tepals 4,

white tinged with pink, glabrous, unequal, outer elliptic, 10–11 × 8–9 mm, inner obovate, 12–14 × 6 mm; androecium yellow, symmetrical, globose, stalked at base, filament column c. 1 mm long; stamens 38–44, to c. 1.5 mm long, filaments to 0.7 mm long; anthers to

0.8 mm long, dehiscent through lateral slits longer than half of the anther, apex truncateretuse. Female flower pedicel 15–22 mm long, pinkish to reddish; tepals (3 or) 4, pink or white tinged with pink, unequal, outer broadly ovate, 7–8 × 7–8 mm, inner ovate to elliptic,

5 × 2–4 mm, glabrous; ovary 7–8 × 4 mm (excluding the wings), ellipsoid, green, greenish tinged with pink, or pink, wings subequal, to 4 mm wide at the widest point (middle part), convex to cuneate at the base and apex; style to c. 3 mm long, fused at base for c. 1 mm; stylodia 3; stigmas 3, U-shaped, stigmatic surface spirally twisted, papillose. Fruit pedicel to 22 mm long; dry capsule dehiscing through lines along the wing attachment, seed-bearing part ellipsoid, 9–10 × 4–6 mm, wing shape as for ovary, wings to 6 mm at the widest point (middle part). Seeds barrel-shaped, 300–320 μm long, collar cells> 1/2 the length of the seed.

Distribution. Indonesia, Timor-Leste; endemic to Timor ( Figure 2 ).

Habitat and ecology. In crevices and on ledges on limestone cliffs, cave entrances and limestone boulders, in semi-shade, from 250 to 1300 m elevation.

Etymology. Greek, stilpnos (‘sparkling’, ‘glittering’) and - phyllos (‘-leafed’) – a reference to the way light reflects from the lower leaf surface (see Figure 1E ).

Proposed IUCN conservation category. Endangered (EN) B1ab(iii)+2ab(iii). The recent collections of this species in Viqueque Municipality, Timor-Leste, were made in areas that showed severely disturbed vegetation and ongoing major anthropogenic disturbances including grazing of livestock, road construction and settlements. The collection on Monte Munde Perdido was made from a small limestone rock outcrop surrounded by a grass pasture. Although Begonia stilpnophylla was locally abundant and tolerated some degree of disturbance, some individuals in degraded, sun-exposed habitats showed clear signs of sun damage. One recent collection was made in the legally protected Nino Konis Santana National Park, but there is very limited enforcement, and disturbance by livestock grazing, logging and fire could be observed at the margin of the National Park. Timor is botanically poorly explored, but given that this species seems to be restricted to limestone outcrops, the observed ongoing disturbances of its habitats, its fragmented distribution, and based on currently available material, an extent of occurrence of less than 5000 km 2, it is assessed as Endangered.

Notes. The leaf morphology of Begonia stilpnophylla , including the relatively long petioles, relatively large, basifixed leaf laminas with a sinuate, repand or sometimes shallowly lobed leaf margin, and distant, small and frequently reflexed teeth, is similar to the leaf morphology found in two species from Bali, B. pseudomuricata and B. lugrae . Differences from Begonia pseudomuricata are elaborated on in the diagnosis. Begonia lugrae has characteristic semicircular stipules and very long petioles (24–33.5 cm long) that are longer than the inflorescences ( Undaharta et al., 2015), whereas in B. stilpnophylla the stipules are ovate-triangular and the petioles to 12.8 cm long and shorter than the inflorescences, which can reach to 36 cm in length.

Additional specimens examined. INDONESIA. Lesser Sunda Isles , Timor : Nasimetan, S of Kapan, 900 m elevation, 17 iii 1939, S. Bloembergen 3488 ( BO, K) .

TIMOR-LESTE. Timor: Muapitine, Plateau of Fuiloro , Lautem, 350 m, 19 xii 1953, C. G. G. J. van Steenis 18143 ( BM, L [ L2469474 ]) ; Mt Paitxau [Paitchau] Range, near Malahara , Lautem, 830 m elevation, 1 iii 2006, I. D. Cowie 11048 ( L [ L3737987 ]) ; Port. Timor , 1 i 1962, R. Cinatti 298 ( L [ L2469461 ]) ; Viqueque Municipality, Monte Mundo Perdido , 1289 m elevation, 29 viii 2022, D. C. Thomas 3492 ( E, SING) ; Viqueque Municipality, Loihuno , 257 m elevation, 29 viii 2022, D. C. Thomas 3493 ( E, SING) .

Figures

Figure 1. Begonia stilpnophylla D.C.Thomas & Ardi, sp. nov. A, Habit; B, leaf, abaxial surface; C, leaf, adaxial surface; D, rhizome and stipules; E, leaf margin with reflexed teeth; F, dichasial-cymose inflorescence; G, female flower, side view; H, female flower, front view; I, male flower, front view; J, stamens; K, fruit; L, ovary, cross-section; M, seed. Scale bars: B, C and F, 10 cm; D, 2 cm; E, G and K, 1 cm; H, 5 mm; I, 12 mm; J, 1 mm; L, 3 mm; M, 300 μm. All photographs of D. C. Thomas 3494, taken by D. C. Thomas.

Figure 2. Distribution of Begonia stilpnophylla D.C.Thomas & Ardi, sp. nov. (red circles) on Timor, Lesser Sunda Isles. Graticules indicate degrees of latitude and longitude.