Begonia droseroides C.I Peng, Rubite & C.W. Lin, 2018
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publication ID |
https://doi.org/ 10.11646/phytotaxa.347.3.1 |
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persistent identifier |
https://treatment.plazi.org/id/03947745-E340-FFD1-6682-787FFEEB71FA |
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treatment provided by |
Felipe |
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scientific name |
Begonia droseroides C.I Peng, Rubite & C.W. Lin |
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1. Begonia droseroides C.I Peng, Rubite & C.W. Lin View in CoL , sp. nov. ( Figs. 1 View FIGURE 1 & 2 View FIGURE 2 ).
Type:— PHILIPPINES. Luzon, Aurora, Maria Aurora, Barangay Zazal, at bank of Cabualan River, Bazal-Baubo Watershed, on semishaded, wet, rocky cliff above water, elevation ca. 165 m, 15°48’44”N, 121°24’23”E, 28 October 2011, Peng 23418, with Chien-I Huang, Rosario R. Rubite, Danilo N. Tandang, John Rey C. Callado (holotype PNH, isotype HAST).
Monoecious rhizomatous herb. Rhizome short creeping, crimson, 3 to 8 cm or longer, 4.5 − 8 mm thick, subglabrous, internodes 3 − 7 mm long. Stipules persistent, reddish, ovate-triangular, 8–12 mm long, 7–10 mm wide, herbaceous, strongly keeled, few fleshy red hairs fused into at the base of the keel, keel densely hirsute abaxially, margin entire, apex aristate, arista ca. 2 mm long. Leaves alternate, petiole terete, reddish, 4.3 − 12 cm long, 2.5 − 4 mm thick, densely pale brown appressed sericeous, sometimes with few fleshy red hairs at base of petiole; leaf blade asymmetric, oblique, widely ovate, 5.4 − 8.2 cm long, 4.4–7 cm wide, broad side 3–5.2 cm wide, basal lobes cordate, 1.9–3.7 cm long, midrib 3.5–5 cm long, apex obtuse to rounded, margin slightly scalloped, subentire and lined with puberulous, hairs red; leaf thick chartaceous, adaxially green, glabrous; abaxially pale green, red puberulous on all veins; venation basally ca. 7– palmate, midrib distinct, ca. 2 secondary veins on each side, other primary veins branching dichotomously or nearly so, tertiary veins reticulate. Inflorescence axillary, bisexual, cymosely branching panicle 12–22 cm long, peduncle 7–19 cm long, dichasial cymes arising directly from rhizome, branched 2–3 times, erect or ascending, reddish, densely white glandular hairs, slightly viscose; protandrous. Bracts reddish, hyaline, deciduous, those at basal node of inflorescence ovate, boat-shaped, ca. 7 mm long, 4 mm wide, apex mucronate apiculate, margin entire, abaxially glandular hairs; bracts at summit of inflorescence similar but smaller. Staminate flower: pedicel 0.8–1.6 cm long, sparsely glandular hairs or glabrous; tepals 4, white, outer 2 widely obovate to suborbicular, 1.1–1.6 cm long, 1.0– 1.7 cm wide, abaxially sparsely glandular hairs, inner 2 oblanceolate to obovate, 0.9–1.7 cm long, 0.3–0.6 cm wide, apex rounded; androecium actinomorphic, 0.4–0.6 cm across; stamens yellow, 34–43; filaments sub-fused at base; anthers obovate, ca. 1 mm long, 2-locular, apex obtuse or rounded, subequal at filaments. Pistillate flower: pedicel 1.1–1.7 cm long, glabrous; tepals 5, white, outer 2 obovate to widely obovate, 0.8–1.4 cm long, 0.7–1 cm wide, glabrous; inner 3 oblanceolate to obovate, 1.1–1.5 cm long, 0.3–0.65 cm wide, apex obtuse or rounded; ovary green to reddish, body trigonous-ellipsoid, ca. 6 mm long, 2.5 mm thick (wings excluded), glabrous; 3-winged, unequal, wings 6–8 mm long, lateral wings narrower, narrowly crescent-shaped, 2–3 mm wide, abaxial wing much protruded, trapezoid to crescent-shaped, slightly cordate at proximal, slightly truncate at distal, 4–6 mm wide, margin entire; ovary 3-locular, placenta bilamellate; styles 3, with a longly fused at base, yellow, ca. 3 mm long, stigma spirally twisted. Capsule pendent, pedicel 1.7–2.3cm long, tepals deciduous; body narrowly trigonous-ellipsoid, 7–9 mm long, 3.5–5 mm thick (wings excluded), greenish or reddish when fresh; wings unequal, 11–14 mm long; lateral wings 3–5 mm wide, abaxial wing 7–11 mm wide.
Etymology: — Named for its resemblance to Drosera , as the species has viscous stalked-glandular hairs that densely clothe the inflorescence, and which we observed to trap some small insects. The glandular hairs are also present in bracts and abaxial tepals of the staminate flower.
Distribution and habitat:— Begonia droseroides is known only from a small area along Cabualan River in eastern Luzon (Aurora Province). It occurs on a semi-exposed rocky slope above river water, at ca. 165 m elevation, very rare locally.
Notes:— Begonia droseroides is somewhat similar to Begonia luzonensis Warburg (1904: 52) in having broadly ovate leaves, 3-locular ovary with unequal wings, but are distinct in the congested rhizome internodes (3–7 mm vs. 20–50 mm) with scattered hairs (vs. subglabrous); sericeous petioles (vs. hirsute); uniformly green lamina (vs. light green to silvery grey between the veins), slightly scalloped/subentire margin (vs. irregularly denticulate); and the densely glandular hairy (vs. glabrous) inflorescence. This species has been sampled in the biogeographic study of Hughes et al. (2015) as Begonia sp 6 , and falls within a clade consisting mostly of species from Luzon with an origin ca. 2.5 mya.
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