Taxonomic studies on Begonia (Begoniaceae) in Myanmar I: three new species and supplementary description of Begonia rheophytica from Northern Myanmar Author Maw, Mya Bhone Author Ding, Hong-Bo Author Yang, Bin Author Win, Pyae Pyae Author Tan, Yun-Hong text PhytoKeys 2020 138 203 217 http://dx.doi.org/10.3897/phytokeys.138.38721 journal article http://dx.doi.org/10.3897/phytokeys.138.38721 1314-2003-138-203 37174C2A6257592B83BED9D2E2CAA79B Begonia rheophytica M. Hughes, Edinb. J. Bot. 76(2): 2. 2019 Figure 5 Type. Myanmar. Hills east of the Mali Hka, 2000-3000 ft, xii 1930, Kingdon-Ward 9067 (holotype: BM000896328; isotypes: BM000896327, NY02652766). Description. Herb, rhizomatous, firmly rooted to rock. Rhizome 2.5-4.0 cm long and 0.5-1.0 cm in diam., internode 0.2-0.7 cm long. Stipule reddish brown, eventually deciduous, narrowly triangular, 0.7-1.0 x 0.3-0.5 cm, keeled, margin entire, glabrous. Leaf petiole deep red or deep red to green, turns to brown in mature leaves, sparsely or densely white pilose, 4-17 cm in length, deeply grooved above; blade symmetric, narrowly lanceolate, 13.4-18.2(-21) x 2.2-4.0 cm, base attenuate, sometimes unequal, margin red, toothed, teeth tipped by a short ciliate, sometimes undulate, apex elongate; adaxially dark green, glabrous; abaxially pale green, veins densely or sparsely white pubescent; venation pinnate, 5-7 pairs of veins, reddish green in young leaves, red in mature leaves. Inflorescence axillary, cymose, peduncle erect, 14-20 cm long, reddish green or pale reddish brown, sparsely hairy; bract caducous, broadly ovate-triangular (or ovate-lanceolate), 6-8 x 3-5 mm, purplish red to dark yellow-green, margin entire, hairless. Staminate flower : pedicel 1.9-2.1 cm, pale pink (or) pinkish white, sparsely hairy; bracteoles ca. 3 mm, narrowly ovate, dark yellow green, margin entire, hairless, soon falling, tepals 4, unequal, inner 2, elliptic, 1.4-1.7 x 0.8-1.0 cm, pure white to pinkish, margin entire, outer tepals 2, broadly ovate, 1.1-1.8 x 1.1-1.5 cm, pure white or pinkish, tip rounded, margin entire; androecium actinomorphic; stamens numerous, filaments fused at base; anther golden yellow, narrowly oblong, apex rounded. Pistillate flower : pedicels 2-3 cm, reddish or purplish red, hairless; bracteole narrowly ovate 6-8 x 3-5 mm, dark yellow green (sometimes crystal white), soon falling; tepals 5-6, unequal, outer 2, equal, broadly ovate, tip rounded, 0.7-1.2 x 0.8-1.2 cm, pure white or white to rosy pink, inner 3 or 4, unequal, 3 larger, 0.8-1.2 x 0.7-1.0 cm, elliptic, pure white or pinkish, tip rounded, 1 smaller, ca. 0.8 x 0.3 cm, pure white, crescent, styles 2, free, stigma bifid with twisted bands, greenish yellow, 4-5 mm long, ovary purplish red, ca. 9-15 mm long, 2-4 mm in diam., wings 3, unequal, placentation axile, locules 2, placentae 2 per locule. Capsule nodding, 3-winged, unequal, major wing 8-12 mm long, lateral wings 2-3 mm long. Figure 5. Begonia rheophytica M. Hughes (photographed by H.B. Ding and Y.H. Tan) A habitat B staminate flower (front view) C pistillate flowers D inflorescences E staminate flowers (front and back view) F single leaf (back view) G single leaf (front view) H pistillate flower I ovary with gynoecium, pedicel and bracts J ovary with gynoecium K bracts L pedicel M androecium with pedicel N tepals of staminate flower O tepals of pistillate flower P capsule Q-R cross section of ovary. Distribution. Only found in Putao District, Kachin State, Northern Myanmar. Additional specimens examined. Myanmar, Kachin State, Putao District, Camp 1 to Namti (Camp 2), understory herbs in tropical rain forest, 27°24'36.80"N , 97°39'24.38"E , 801 m, 12 December 2018, Myanmar Exped. M3427 (HITBC!; RAF!); Kachin State, Putao District, near around Camp 1, understory herbs in tropical rain forest, 27°24'18.70"N , 97°36'24.18"E , 850 m, 11 December 2018, Myanmar Exped. M3334 (HITBC!; RAF!); Kachin State, Putao District, humid rocks near streams or near caves by waterfall of tropical montane forest, 27°24'46.31"N , 93°39'36.28"E , 808 m, 16 December 2017, Myanmar Exped. M3747 (HITBC!, RAF!). Note. This species was originally described by Hughes et al. (2019) from the male flowering plant only. Here, we provide a supplementary description of B. rheophytica with a detailed monograph of female flowers from Putao, Kachin State, Northern Myanmar.