Research Article |
Corresponding author: Yu-Min Shui ( ymshui@mail.kib.ac.cn ) Academic editor: Kang Ming
© 2018 Wen-Hong Chen, Xiao-Hua Jin, Yu-Min Shui.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Chen W-H, Jin X-H, Shui Y-M (2018) Rediscovery and amended descriptions of Begonia kingdon-wardii (Begoniaceae) from North Myanmar. In: Jin X-H, Shui Y-M, Tan Y-H, Kang M (Eds) Plant diversity in Southeast Asia. PhytoKeys 94: 59-64. https://doi.org/10.3897/phytokeys.94.21753
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Begonia kingdon-wardii Tebbitt was rediscovered in 2014 from Myanmar after 67 years based on its last collection in 1937. Its previously unknown female flower and inaccurate morphology of leaf and ovary have been additionally described. This species belongs to Begonia sect. Sphenanthera (Hassk.) Warb. due to its dioecious habit, 3-locular ovary, berry fruits and thick placenta segments. Morphologically, it is similar to Begonia gulinqingensis S. H. Huang & Y. M. Shui in the leaf shape, placentation and fruit shape, but different in its dioecious plants, pliciform leaves, two-petalled female flowers and berry fruits. The rediscovery of this amazing living species will attract significant interest for scientific research and horticultural application.
Begonia , Begonia kingdon-wardii , Begonia sect. Sphenanthera, Myanmar, Rediscovery
Begonia L. includes more than 1800 species which are widely distributed in tropical and subtropical areas (
Begonia kingdon-wardii was first reported in 2007 based on the holotype specimen collected from Northern Myanmar in 1926 (Fig.
Begonia kingdon-wardii was named after Frank Kingdon-Ward, a famous plant hunter in the earlier period of the 20th century. For the purpose of collecting seeds of beautiful hardy plants and of dried specimens for English gardens, he carried out many expeditions in N Myanmar, NE India (Assam) and SW China (SE Tibet and NW Yunnan) from 1911 (
Myanmar, Kachin Mts E of Fort Hertz, 27°20'N, 97°30'E, alt. 900 m, Aug. 1926, Kingdon-Ward 7341 (holotype, K000037101!; isotype, K000037102!).
Handwriting annotation from the holotype specimens (Fig.
Plants terrestrial, perennial; stems rhizomatous, 3–10 cm long, 0.2–0.4 cm diam., with fibrous roots on node and 0.5–0.8 cm long internode. Stipules caducous, lanceolate, 1.1–1.3 × 0.4–0.5 cm, margin entire, apex acuminate. Leaf alternate, pliciform, rotund, 10–16 cm diam., margin entire, symmetric on base, usually 4–7-palmatifid venation; adaxially glabrous and serpentinous, green lines and 3–5 spots along each main nerve, abaxially red and pubescent along the main nerves. Petiole 10–18 cm long, densely pubescent. Inflorescences axillary, cymose, dichasial, with separate male and female individuals; peduncles 3–5 cm long; bracts greenish, ovate, 8–9 × 3–4 mm, persistent during flowering. Bracteoles similar to and slightly smaller than bracts; petals white, glabrous on both sides. Male flower: petals 4; outer 2, ovate, 1.2–1.4 × 0.6–0.7 cm, inner 2, elliptic, 0.5–0.6 × 0.2–0.3 cm; androecium actinomorphic, 0.5–0.6 cm diam., filaments free below, anthers oblong, almost equal to the filaments, dehiscent with laterally and obliquely longitudinal slits, connective slightly extended and truncate on the top. Female flower: petals 2, broadly elliptic, 0.9–1× 1.1–1.3 cm; ovary wingless, obtusely 3-hooked, 3-locular, placentation axial, placenta segments thick, 2 per locule, ovules present on both sides of placental branches; styles 3, forked twice, caducous in fruit, stigmas spiralled into a band. Fruit triangular berry-like, pendulous, with an in distinct beak. Flowering Oct. to Nov., Fruiting from the first of Nov. to Oct. of the next year.
Only seen in Kachin State, Myanmar.
Upper Burma (=Myanmar): Kachin Hills, 30 November, 1912, collect. Capt. & M. Joppin 4378 (K!); Myanmar, Kachin, Putao, on shaded banks and rocks, 27°20'N, 97°30'E, alt. 900 m, Dec. 10 1937, Kingdon-Ward 13569 (BM!); Myanmar, Kachin State, Putao, Wasadam village, alt. 860 m, 27°30'09"N, 97°11'45"E, near the stream in the Musa forests, occasional, Oct. 15, 2014, Putao Exped. 311 (KUN!, PE!); Myanmar, Kachin State, Putao, Wasadam village, alt. 900 m, 27°30'06"N, 97°11'44"E, along the moist slope in the Musa forests, occasional, Oct. 25, 2014, Putao Exped. 1230 (PE!).
In Begonia sect. Sphenanthera, Begonia kingdon-wardii is unique in the pliciform leaf and female flower with two tepals (Doorenbos et al. 1999;
The rediscovery of its living plants provides researchers an opportunity to explore its taxonomic description and horticultural value in North Myanmar. This species with very rare individuals is distributed in a restricted area in Northern Myanmar and grows in the very shady and dark places under the forests. Its flowers are near the ground under the leaves, so that this habit influences the pollination and fruit setting. Another important and interesting habit may be that the fruits need over one year to become mature as some species [B. handelii Irmsch. and B. silletensis (A. DC.) C. B. Clarke] in Begonia sect. Sphenanthera. Besides, the pliciform leaf of the living plant is difficult to be observed on the holotype (Figs
The images of Begonia kingdon-wardii Tebbitt (Putao Exped. 311 in PE and KUN) A Male plant B Male inflorescences C Face view of male flower D Female plant E Female inflorescences F Face view of female flower G Leaf blade adaxially H Leaf blade abaxially I Middle section of ovary in flower showing two placenta segments per locule J Inferior section of ovary in flower K Middle section of mature berry-like fruit showing thick placenta segments. Scale bars: A, D 10 cm B, E 1 cm C, F 1 cm G, H 4 cm I, J, K 1 cm. All photographed by Yu-Min Shui.
We are thankful to Professor Zhi-Duan Chen, Dr. Sheng-Xiang Yu and Dr. Bing Liu in the Institute of Botany, Chinese Academy of Sciences, Mr. Han Kyaw Kyaw and Mr. Han Nyi Zaw in Hkakaborazi National Park, Putao, Kachin State, Myanmar, for their help during the field survey. This study is supported by National Natural Science Foundation of China (grant no. 31370228, 31770251, 31070174, 30270109), the funding from Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences (2015CASEABRI001) and Science and Technology Basic Work (2013FY112100).