Begonia tarangban Rubite, C. Justo, P. Villasenor &amp; C. W. Lin. A, B. Habit 2021, sp. nov.
Creators: name: Rubite, Rosario Rivera
name: Justo, Celeena Aimeree De Guzman
name: Villaseñor, Patricka Coliflores
name: Delos Angeles, Marjorie D.
name: Tandang, Danilo N.
name: Lin, Che-Wei
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Magnoliopsida
Cucurbitales
Begoniaceae
Begonia
Begonia tarangban

description: 2. <i>Begonia tarangban</i> Rubite, C. Justo, P. Villaseñor &amp; C.W. Lin, <i>sp. nov</i>. (Figs. 4 &amp; 5) <b>Type:—</b> PHILIPPINES. Samar Island, Province of Samar, City of Calbayog, Tarangban Falls, growing along the shaded moist rocks and soils surrounding the falls, elevation 160 m, 12°15′7′′N, 124°23′56′′E, 9 December 2018, <i>R</i> <i>.</i> <i>Rubite 998</i> (holotype PNH). Monoecious perennial herbs. Stem green to brown, sparsely hirsute (hairs 1–3 mm, light brown) prostrate, 25–43 cm long, 5–8 mm in diameter, internodes 4–6 cm. Stipules persistent, pink, asymmetrically ovate-triangular, 11–14 × 9–14 mm, strongly keeled and hirsute abaxially with a tuft of fimbriae at the base, margin entire, apex aristate. Leaves alternate, petiole terete, brown 14−18 cm long, 5−7 mm thick, lanate (1–3 mm whitish); blade obliquely ovate, 9–14 × 7–12 cm, apex attenuate, base cordate, margin shallowly undulate almost entire; leaf blade thickly chartaceous, adaxial surface green with darker green to almost black veins, glabrous, abaxial surface maroon with sparse hairs on veins, veins brownish green, pilose (1–2 mm whitish), primary veins 6–8. Inflorescence 23–32 cm long axillary, arising directly from the rhizome, dichotomously branching <i>ca.</i> 4 times; peduncle light brown, erect, 17–25 cm long, 4–6 mm in diameter, glabrous; pedicels 10–12 mm erect to ascending in staminate flowers, horizontal in pistillate flowers. Bracts (residual) creamy green to pinkish, hyaline, deciduous, glabrous, wide ovate, boat-shaped, apex acute, margin entire. Staminate flowers: tepals 2+2 glabrous, outer upper lobe adaxial surface pinkish white abaxial surface reddish, orbicular, lower lobe white 11–13 × 10–12 mm, inner pair white, obovate 9–12 × 4–5 mm; stamens 25–35; filaments 0.5 mm long united at the base; anthers yellow, obovate, apex rounded <i>ca</i>. 1 mm long. Pistillate flowers: tepals 2+2 glabrous, outer upper lobe adaxial surface pinkish white abaxial surface reddish, orbicular, lower lobe white 10–12 × 9–11 mm, inner pair white, obovate 9–11 × 4–5 mm; ovary elliptic, green with pink outline 8–10 × 4–5 mm, three-locular, placentae axile, bilamellate; styles three, 5 mm long, stigma yellow; wings unequal, triangular, abaxial wing 8–10 × 4–6 mm, lateral wings 8–10 × 3–4 mm, apex truncate, base acute to rounded, glabrous; Capsule nodding, pedicel 1.0– 1.5 cm long, tepals deciduous; 12–15 × 10–12 mm (wings included). <b>Etymology</b>: <b>—</b> Named after the Tarangban Falls, where the new species was discovered. <b>Distribution and habitat:—</b> <i>B. tarangban</i> is endemic to Tarangban Falls, Calbayog City, Samar Island. It grows on semishaded rocky slopes near the falls at 160 m in elevation. <b>Notes:—</b> <i>B. tarangban</i> is similar to <i>B. biliranensis</i> in having ovate stipules, obliquely ovate, strongly inequilateral cordate leaves where adaxial surface is glabrous and abaxial surface is associated with hairs at the veins; long petioles (11–18 cm); long inflorescence dichotomously branching 4 to 5 times. However, the new species differs in having long internodes 4−6 cm (vs. crowded leaves); stipules hirsute abaxially with a tuft of fimbriae at the base (vs. glabrous); smaller lamina (9–14 × 7–12 vs. 15–22 × 10–15); longer peduncle (17–25 vs. 11–18 cm); larger flowers (22–26 × 19–24 vs. 11–12 × 11–12 mm); capsule wings unequal (vs. equal) and wings triangular (vs. rounded). <b>Proposed Conservation Status:—</b> <i>B. tarangban</i> is known only from the type locality in Tarangban Falls, Calbayog City. Although the area is protected as part of the Samar Island Natural Park, habitat disturbance brought about by human activities such as tourism may have a negative impact on the species. Therefore, following the IUCN criteria <i>B. tarangban</i> is hereby proposed as Vulnerable (VU D2) (IUCN Standards and Petitions Committee, 2019).
description: Published as part of <i>Rubite, Rosario Rivera, Justo, Celeena Aimeree De Guzman, Villaseñor, Patricka Coliflores, Delos Angeles, Marjorie D., Tandang, Danilo N. &amp; Lin, Che-Wei, 2021, Three new species of Begonia (section Baryandra, Begoniaceae) from Samar Island, the Philippines, pp. 263-274 in Phytotaxa 516 (3)</i> on pages 267-269, DOI: 10.11646/phytotaxa.516.3.5, http://zenodo.org/record/5372506