Tuesday, July 3, 2018

[Botany • 2018] Begonia medogensis • A New Species of Begoniaceae from Western China and Northern Myanmar


Begonia medogensis JianW.Li, Y.H.Tan & X.H.Jin

in Li, Tan, Wang, et al., 2018.

Abstract
Begonia medogensis JianW.Li, Y.H.Tan & X.H.Jin, a new species of Begoniaceae, is described and illustrated by colour photographs. Begonia medogensis is distributed in western China and northern Myanmar. It has erect stems, is tuberless, has many triangular to lanceolate leaves, base slightly asymmetric, margins remotely and irregularly denticulate; staminate flowers have 4 perianth segments, with outer 2 segments broadly ovate, inner 2 spathulate; pistillate flowers have 5 perianth segments, unequal, outer 4 broadly ovate, inner 1 spathulate. The new species is assigned to section Platycentrum and can easily be distinguished from the other species in the section.

Keywords: Begonia, Begonia medogensis, sect. Platycentrum, new species, China, Myanmar


Figure 1. Begonia medogensis JianW.Li, Y.H.Tan & X.H.Jin.
 A Habitat B–E Flowers F Pedicel and ovary (showing large wing) G Male flowers (face view) H Ovary (showing loculus) I Flowers J Dissection of female flower K Dissection of male flower L Leaves M Anther with filament (under dissection mirror, bar = 1 mm) N Female flower (face view).
(photographed by Jian-Wu Li).

Begonia medogensis JianW.Li, Y.H.Tan & X.H.Jin, sp. nov.

Diagnosis: Begonia medogensis is morphologically similar to B. goniotis, B. griffithiana, B. nepalensis and B. sandalifolia, but can be easily distinguished from them by having leaves ovate-lanceolate, 6.0–8.0 × 1.5–2.5 mm, base slightly asymmetric, margins remotely and irregularly denticulate; triangular to lanceolate stipules; staminate flowers with outer 2 segments broadly ovate, inner 2 spathulate; pistillate flowers with perianth segments unequal, outer 4 larger, broadly ovate, inner 1 smallest, spathulate; cylindroid ovary, larger wing oblong, apex truncate.

Type: CHINA. Tibet, Medog County, Beibeng town, semi-evergreen forest in a subtropical area, 29°15'09"N, 95°13'31"E. 1381 m a.s.l., 16 November 2017, flowering, Xiaohua Jin, Jianwu Li, Xilong Wang & Chengwang Wang 19331 (holotype: HITBC!, isotype: HITBC!, PE!, K!)


Distribution and habitat: This new species grows in subtropical areas in Beibeng town, Medog County, Tibet, China, at an elevation of 700–1400 m and in Putao district, Kachin state, Myanmar, at an elevation of 600–1200 m.

Etymology: The species is named after the holotype locality, Medog County, in Tibet, China.


 Jian-Wu Li, Yun-Hong Tan, Xi-Long Wang, Cheng-Wang Wang and Xiao-Hua Jin. 2018. Begonia medogensis, A New Species of Begoniaceae from Western China and Northern Myanmar. PhytoKeys.  103: 13-18.  DOI: 10.3897/phytokeys.103.25392