Wednesday, September 14, 2016

[Botany • 2016] Begonia lamxayiana Souvann. • A New Species (Begoniaceae) from Lao PDR

 Begonia lamxayiana Souvann.

 Begonia lamxayiana Souvann. is described and illustrated.

KEYWORDS: Begonia, new species, Lao PDR, biodiversity, Taxonomy

FIGURE 2.   Begonia lamxayiana Souvann. 
A. Plant shoot with inflorescences; B. Inflorescences at stem; C. Cross section of ovary; D. Male flower, front view; E. Male flower, lateral view; F. Stipules; G. Female fl ower, lateral view; H. Female flower, front view.
Photos by K. Souvannakhoummane from Lamxay et al. VL 2198.  

 Distribution and ecology.— Begonia lamxayiana is endemic to Khamkeut district, Bolikhamxai province. It is known only from type locality such as valley terrains or stream banks, on shaded steep slopes in very wet primary evergreen forest, associated with Magnolia sp., Alpinia sp., Zingiber sp., Anoectochilus sp., Bamboo, and terrestrial ferns, elevation ca. 570 m.

Etymology.— The epithet is in honour of Assist. Prof. Dr. Vichith Lamxay, who collected the type specimens.

Notes.— This species is similar to Begonia boisiana Gagnep. (found in Vietnam) but differs by having glandular hairs on the stem (vs. glabrous), leaves with bristles on the adaxial surface (vs. glabrous), zygomorphic androecium (vs. actinomorphic) and semi-persistent bracts, margin ciliate, pale green (vs. persistent bracts, margin dentate, pale purple or white). It is similar to B. cucphuongensis H.Q. Nguyen & Tebbitt (found in Vietnam) but differs by having leaves with bristles on the adaxial surface and dense glandular hairs along the veins abaxially (vs. both surfaces glabrous), anther apex emarginated (vs. truncate to rounded), female fl owers with 5 tepals (vs. female fl owers with 3 tepals) and stigmatic band kidney-shaped and papillose (vs. stigmatic lunate).

Keooudone Souvannakhoummane, Mark Hughes and Soulivanh Lanorsavanh. 2016.  Begonia lamxayiana Souvann. (Begoniaceae): A New Species from Lao PDR.
THAI JOURNAL OF BOTANY [วารสารพฤกษศาสตรไทย]. 8(1): 1–5.