Sunday, February 4, 2018

[Botany • 2018] Rediscovery and Amended Descriptions of Begonia kingdon-wardii (Begoniaceae) from North Myanmar


Begonia kingdon-wardii  Tebbitt

in Chen, Jin & Shui, 2018.
    DOI:  10.3897/phytokeys.94.21753 

Abstract
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.

Keywords: Begonia, Begonia kingdon-wardii, Begonia sect. Sphenanthera, Myanmar, Rediscovery

Begonia kingdon-wardii Tebbitt (Putao Exped. 311 in PE and KUN) Male plant Male inflorescences Face view of male flower Female plant Female inflorescences Face view of female flower Leaf blade adaxially Leaf blade abaxially.

Begonia kingdon-wardii Tebbitt 
in Kew Bulletin 62: 143, 2007

Figure 2. 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.

Discussion
In Begonia sect. Sphenanthera, Begonia kingdon-wardii is unique in the pliciform leaf and female flower with two tepals (Doorenbos et al. 1999; Shui et al. 2002). It is obviously different from Begonia burkillii Dunn in B. sect. Sphenanthera and B. rockii Irmsch. in B. sect. Platycentrum in the locules of ovary and leaf shape. Morphologically, this species is also similar to B. gulinqingensis S. H. Huang & Y. M. Shui (Begonia sect. Diploclinium) in the leaf shape, placentation and fruit shape, but different in its dioecious plant, pliciform leaf, female flower with two sepals and berry fruit. It is also similar to B. leprosa (Begonia sect. Leprosae) in the leaf shape, especially the texture of the leaf blade and B. zhengyiana Y. M. Shui (Begonia sect. Coelocentrum) in shape of the leaf blade and fruit.

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 1, 2). Now, the rediscovery not only reveals the need to undertake more surveys in North Myanmar, but also fills the gap about the deficient data of the species indicated by Tebbitt (2007) and so can bring an amazing plant to mankind for research and horticultural use (Fig. 2).


 Wen-Hong Chen, Xiao-Hua Jin and Yu-Min Shui. 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 (EdsPlant diversity in Southeast AsiaPhytoKeys. 94; 59-64.  DOI:  10.3897/phytokeys.94.21753


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