B. calciphila

Herbs perennial, monoecious, lithophytic. Rhizomes creeping, to 30 cm or longer, internodes 1.5–4.5 cm long, 6–8 mm across, reddish or whitish hirsute, hairs 3–3.5 mm long, glabrescent. Stipules ovate, 7–12 mm long, 4–7 mm wide, apex caudate, margin entire, abaxially hirsute, hairs 1.5–3.5 mm long. Leaves alternate; petiole brownish, 2–7 cm long, villous, hairs 3.5–4 mm long, brownish or reddish; leaf blade orbicular-ovate to ovate, apex acute, base obliquely cordate, 7–10.5 cm long, 5.5–8.5 cm wide, margin undulate, densely ciliate; primary veins 6–8, palmate, veinlets reticulate; adaxially sparsely or densely scabrous, trichomes ca. 1.5 mm long; abaxial surface reddish-hirsute on veins, trichomes multicellular, ca. 1 mm long. Inflorescence axillary, with 2–5 flowers in dichasial cymes, peducle tinged reddish, ca. 8 cm long, glabrous; pedicel 8–9 mm long, glabrous. Bracts ovate, margin sparingly reddish ciliate, 3.5–4 mm long, 2.5–3 mm wide. Staminate flower: tepals 4, outer 2 orbicular-ovate to ovate, margin entire, white or tinged pinkish, 9–15 mm long, 9–13 mm wide, abaxially sparsely reddish-hirtellous; inner 2 oblanceolate, white, 11–13 mm long, 3.5–4 mm wide; androecium zygomorphic, stamens 20–25, yellow, filaments 0.8–1 mm long, anthers ca. 1.5–1.7 mm long. Carpellate flower: tepals 3, glabrous, outer 2 orbicular or suborbicular, tinged pinkish, 12–14 mm long, 12–13 mm wide, margin entire; inner 1 oblanceolate, 8–10 mm long, 3–5 mm wide, white; ovary trigonous-ellipsoid, pinkish, 7–8 mm long, 4–5 mm across, glabrous, 3-winged, abaxial wing crescent-shaped, 3–5 mm tall, lateral wings 2–3 mm tall; styles 3, ca. 4 mm long, fused to 1/3 at base, bifurcating with yellow stigma forming a continuous U-shaped papillose band. Capsule trigonous-ellipsoid, 7–8 mm long, 4–5 mm across, abaxial wing crescent-shaped to elliptic, 8–9 mm tall, lateral wings crescent shaped, 3–4 mm tall. Seeds many, ellipsoid, truncate at both ends, brownish, 0.4–0.5 mm long, 0.2–0.25 mm thick. Begonia calciphila shares the long creeping habit with B. auritistipula Y.M. Shui & W.H. Chen (2005: 357), a calciphyte in southwestern Guangxi, China. The new species however differs from the latter in the petioles 2–10 cm long (vs. 9–22 cm); leaves orbicular-ovate with an acuminate apex (vs. ovate with an acute apex); leaf adaxial surface scabrous (vs. rugose and setulose); stipules villous (vs. glabrous); and petioles villous (vs. retrorsely hirsute)

• Classification: Species
• Plant Type: Trailing-Scandent
• Botanical Section: Coelocentrum
• Origin: Asia, Vietnam
• Originator: C.I Peng
• Date of Origin: 2015