Begonia medogensis JianW.Li, Y.H.Tan & X.H.Jin, 2018

Li, Jian-Wu, Tan, Yun-Hong, Wang, Xi-Long, Wang, Cheng-Wang & Jin, Xiao-Hua, 2018, Begonia medogensis, a new species of Begoniaceae from Western China and Northern Myanmar, PhytoKeys 103, pp. 13-18 : 13

Begonia medogensis JianW.Li, Y.H.Tan & X.H.Jin sp. nov. Figure 1

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!)

Description.

Perennial herbs, caulescent, erect. Rhizomes short, stout. Stems reddish-purple, densely pubescent, 0.3-1.0 m tall, with internode 6-15 cm long, upper part well-branched, with internode 2-5 cm long. Leaves cauline; stipules persistent, triangular to lanceolate, 6.0-8.0 × 1.5-2.5 mm, apex acuminate to cuspidate; petiole 1.2-2.7 cm long, densely pubescent; leaf blade ovate-lanceolate, slightly asymmetric, 6.0-10.0 × 2.0-3.7 cm, adaxially green, slightly hairy, abaxially greenish-white, hairy on venation, venation palmate-pinnate, 5-8-veined, base slightly oblique, rounded to subcordate, margins remotely and irregularly denticulate, apex caudate-acuminate. Inflorescences terminal and axillary, sub-corymb, monoecious, to 6 cm, sub-pendulous, peduncles 2.7-4.0 cm long, secondary 0.5-1.0 cm long, terminally with 1-5 flowers; floral bracts lanceolate to ovate-lanceolate, 5.0-10.0 × 1.7-5.0 mm, thickly papery, glabrous, apex acuminate. Staminate flowers: pedicel 10-15 mm long; tepals 4, white, outer 2 broadly ovate, 15-17 × 12-14 mm, tinted with pink, glabrous, apex rounded; inner 2 spathulate, 11-14 × 6-8 mm, glabrous, apex obtuse to rounded; stamens 60-80; filaments free, 0.5-1.2 mm long, sub-equal, fused at base into a column; anthers broadly lorate, 0.8-1.1 mm long, apex emarginate. Pistillate flowers: pedicel 11-20 mm long, tepals 5, white, unequal, glabrous, outer 4 broadly ovate, the outmost 2 tinted with pink, 12-14 × 9-12 mm, apex rounded, other 2 slightly larger, 13-15 × 10-12 mm, apex obtuse to rounded; the inner 1 smallest, spathulate, 8-10 × 7-9 mm, apex rounded; ovary glabrous, 2-loculed; placentae axile, bilamellate; styles 2, fused at base; stigmas 2-cleft, spiralled. Capsule sub-pendulous, cylindroid, 5.0-8.0 × 1.5-2.5 mm; wings 3, adaxial 1 larger, oblong, 7-9 mm broad, apex truncate, lateral 2 less developed, 2-3 mm broad.

Phenology.

Flowering from October to December.

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.

Additional specimens examined

(paratype). MYANMAR. Putao district , Kachin state, in tropical montane forest, 27°37'15"N, 97°53'14"E. 900 m a.s.l., 1 December 2016, flowering, Myanmar Exped. M 0727 (HITBC!) .

Note.

Morphologically, the new species is similar to B. goniotis , B. griffithiana , B. nepalensis and B. sandalifolia , but differs from them by the shape of stipules and leaves, base and margins of leaves, both male and female flowers having unequal perianth segments, cylindroid ovary etc. (see Table 1 ).

Figures

Figure 1. Begonia medogensis JianW. Li, Y. H. Tan & X. H. Jin. (photographed by Jian-Wu Li). 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).