PlantaeCucurbitalesBegoniaceaeLiJian-WuTanYun-HongWangXi-LongWangCheng-WangJinXiao-Hua Begonia medogensis, a new species of Begoniaceae from Western China and Northern MyanmarPhytoKeys2720182018103131810.3897/phytokeys.103.25392 Begonia medogensis urn:lsid:ipni.org:names:77186060-1 JianW.Li, Y.H.Tan & X.H.Jinsp. nov.Figure 1Diagnosis.

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!)

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).

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. M0727 (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).

Differences between Begonia medogensis, B. goniotis, B. griffithiana, B. nepalensis and B. sandalifolia.

Character B. medogensis B. goniotis B. griffithiana B. nepalensis B. sandalifolia
Steminternode 6–15 cm longinternode 4–10 cm longinternode 3–9 cm longinternode 4–11 cm longinternode 9–20 cm long
Stipulespersistent, triangular to lanceolate, 6.0–8.0 × 1.5–2.5 mmpersistent, ovate, 6–13 × 4–10 mmpersistent, lanceolate, 4–13 × 1–2 mmdeciduous, lanceolatepersistent, oblong, 6–10 × 2–4 mm
Leavespetiole 1.2–1.7 cm long, ovate-lanceolate, base slightly asymmetric, 6.0–10.0 × 2.0–3.7 cm, margins remotely and irregularly denticulate, apex caudate-acuminatepetiole 1.0–4.6 cm long, lanceolate, base strongly asymmetric, 10–15 × 0.6–2.5 cm, margins entire or serrate near apex, apex long acuminatepetiole 0.2–1 cm long, oblong-lanceolate to lanceolate, base strongly asymmetric, 5–18 × 2–5 cm, margins serrulate or with small teeth at ends of the main veins, apex acuminatepetiole 1–3 cm long, ovate-lanceolate, base strongly asymmetric, 15–17 × 4–11 cm, margins shallowly dentate, apex caudate-acuminatepetiole 0.7–1.3 cm long, ovate to oblong, base strongly asymmetric, 10–15 × 3–5 cm, margins entire or serrate, apex acuminate
Male flowertepals 4, outer 2 broadly ovate, 15–17 × 12–14 mm, tinted with pink, inner 2 spathulate, 11–14 × 6–8 mm, white, stamens 60–80, anthers broadly loratenot seentepals 4, outer 2 orbicular to oblong, 4–14 × 2–11 mm, pale pink to white, inner 2 lanceolate to linear, 3–9 × 1–4 mm, pale pink, stamens 20–30, anthers elliptic-globosetepals 2, ovate, 7–10 × 7–9 mm, pale pink to white, stamens 20–40, anthers elliptic globosetepals 4, outer 2 round, 18 × 18 mm, inner 2 oblong, stamens ca. 50, anthers obovoid
Female flowertepals 5, unequal, outer 4 broadly ovate, the outmost 2 tinted with pink, 12–14 × 9–12 mm, other 2 slightly larger, 13–15 × 10–12 mm; the inner 1 smallest, spathulate, 8–10 × 7–9 mmnot seentepals 5–6, equal, 3–4 larger and 1–2 smaller, oblong elliptic to obovate orbicular, outer tepals 6–11 × 5–7 mm, pale pink to white, inner tepals smallertepals 4–5, equal, outer tepals 10–15 × 7–10 mm, pale pink to white, inner tepals smallernot seen
Ovarycylindroid, 5–8 × 1.5–2.5 mm, larger wing oblong, 7–9 mm broad, apex truncateellipsoid, 10–13 × 6 mm, larger wing oblong, 10–16 mm broad, apex roundedoblong-ellipsoid, 5–7 × 2–3 mm, larger wing triangular, 12–18 mm broad, apex obtusenarrowly ellipsoid, 12–15 × 5 mm, larger wing oblong, 15–23 mm broad, apex truncateellipsoid, 13–16 × 6 mm, larger wing oblong, 13–16 mm broad, apex rounded