Begonia fenshuilingensis X.X.Feng, R.K.Li & Z.X.Liu, 2021

Feng, Xin-Xin, Liu, Zhi-Xian, Wei, Dan, Li, Ren-Kun, Huang, Yu-Ni, Guo, Le-Dong, Guo, Wei & Chen, Su-Fang, 2021, Begonia fenshuilingensis, a new species in Begonia sect. Platycentrum (Begoniaceae) from southeastern Yunnan, China, Phytotaxa 527 (4), pp. 266-274 : 267-270

Begonia fenshuilingensis X.X.Feng, R.K.Li & Z.X.Liu , sp. nov. ( Figs 1–2 ) ÷水岭î海ḡ

Type:— China, Yunnan, Jinping County (ṯ平县), Adebo Town (ē得博乡), 22°54′19″N, 103°13′20″E, ( Fig. 3 ), 1600 m a.s.l., in shaded environment, August, 2020, X. X. Feng, R. K. Li & Z. X. Liu (holotype: SYS00236301 , SYS !; isotypes: SYS! & CSH!) .

Diagnosis:— Begonia fenshuilingensis is morphological similar to B. dryadis and B. daweishanensis in rhizome and leaf morphology. However, it differs markedly from both these species in having fleshy wingless trigonous-ellipsoid capsules, not winged and dry dehiscent capsules. According to molecular phylogenetic evidence, Begonia fenshuilingensis forms a monophyletic group with B. hekouensis . However, B. hekouensis has orange flowers and densely villous capsules, easily distinguishing it from the new species.

Description:—perennial evergreen herb, monoecious, 30–50 cm tall. Rhizome stout and creeping, ca. 12–15 cm long and 18–20 mm in diameter, internodes obvious and crowded, covered by triangular, brownish-green, membranous squamae; erect stem only at anthesis, usually yellowish-brown, sparsely pilose. Stipules yellowish-green, translucent, ovate-triangular, pubescent. Leaves 6–8 basal and 3–5 aerial, petiole reddish-brown, 14–16 cm long, densely red pilose; blade asymmetric, widely ovate to elliptic, 10–15 × 8–11 cm; apex caudate, base oblique-cordate; leaf margin triangularly denticulate at young stage and then crenate to entire in mature; venation palmate with 6–8 primary veins, adaxially slightly concave, abaxially convex; leaf blade fleshy, abaxially reddish-brown, pubescent, adaxially green, setulose. Inflorescences arising from an erect stem; dichasial cymes branching two times, peduncle 1.4–4 cm long; pubescent; flowers unisexual, 2–3 flowers per inflorescence; bract fleshy, triangular to widely ovate, yellow-reddish, 15–16 × 8–9.5 mm, densely pubescent. Staminate flower pedicel yellow-reddish, ca. 3 cm long, pubescent nearly same as peduncles; tepals 4, outer 2 tepals ovate to circular, 20–23 × 20–25 mm, adaxially concave, white glabrous, abaxially convex, pinkish-white, densely setulose adaxially; inner 2 broadly obovate, 20–24 × 18–20 mm, margin irregularly entire, white, glabrous; androecium spheroid, ca. 13 mm across; stamens numerous, ca. 4 mm long, anthers golden yellowish, clavate, base cuneate, ca. 2 mm long, apex extended. Pistillate flower pedicels reddish-green, ca. 3 cm long, pubescent; tepals 5, whitish-pinkish, irregularly ovate, obovate or cuneate, sub-equal, 17–27 × 18–29 mm, abaxially sparsely setulose; ovary yellowish-green, trigonous-ellipsoid, 18–23 × 13–16 mm, wing absent, tomentose; 2-loculed, placentae axile, placentae bifid per locule; styles 2, fused at base, golden yellow, ca. 7–9 mm long, apically Y-shaped, stigma spirally U-shaped twisted. Capsule nodding, trigonous-ellipsoid, ca. 20–24 × 14–16 mm, reddish– green, sparsely tomentose with distinct whitish speckles; wings absent.

Distribution and habitat:—Currently only known from one locality at an elevation of 1600 m ( Fig. 3 ). It grows in a shaded environment along a stream.

Phenology:—Flowering May–August, Fruiting September–October.

Etymology:—The specific epithet “ fenshuilingensis ” refers to the Fenshuiling Natural Reserve where the species is distributed.

Conservation status:—Only one population with approximately 200 individuals has been found in the natural reserve.According to the IUCN Red List Categories and Criteria ( IUCN, 2019), B. fenshuilingensis should be assessed as “Vulnerable D2” (VU D2) due to its extremely small geographic distribution and low population size.

Molecular Analysis

The aligned matrix of the ITS sequence data was 793 bp long. Begonia sect. Platycentrum appears monophyletic with a high Bayesian posterior probability (bpp=1) ( Fig. 4 ). Within B. sect. Platycentrum , all 14 species can be divided into five subclades. The five samples of the putative new species form a monophyletic group clustered with B. hekouensis (bpp=1). The morphologically similar begonias including B. daweishanensis and B. dryadis are more distantly related.

Figures

FIGURE 1. Begonia fenshuilingensis drawn by Yunxiao Liu. A. Habit; B. Adaxial leaf blade; C. Abaxial leaf blade; D, E. Bract; F. Staminate flower (adaxial); G. Staminate flower (abaxial); H. Spheroid androecium; I. Stamen; J. Pistillate flower (adaxial); K. Pistillate flower (abaxial); L. Ovary & styles; M. Cross section of ovary; N. Stigma (front view); O. Capsule.

FIGURE 2. Habitat and morphology of Begonia fenshuilingensis X.X.Feng, R.K.Li & Z.X.Liu. A. Habitat; B. Creeping rhizome; C. Membranous squamae; D. Creeping rhizome; E. Stipule; F. Leaf blade (adaxial); G. Leaf blade (abaxial); H. Erect stem with young inflorescence; I. Inflorescence; J. Bract; K. Front view of staminate flower; L. Back view of staminate flower; M. Lateral view of staminate flower; N. Spheroid androecium; O. Front view of pistillate flower; P. Back view of pistillate flower; Q. R. Lateral view of pistillate flower; S. Ovary & style; T. Stigma; U. Cross section of ovary; V. Mature capsule. (Photos: A, V. by R.K. Li; B–U by Z.X. Liu)

FIGURE 3. Distribution of B. fenshuilingensis(★), B. daweishanensis (●), B. dryadis (▲), and B. hekouensis(◆).

FIGURE 4. Bayesian inference phylogeny showing the position of the newly described B. fenshuilinensis within sect. Platycentrum based on nuclear ITS sequences. Nodes with bpp <0.50 have been collapsed. Sectional placement of taxa is indicated by the following abbreviations: Coe: Coelocentrum, Dip: Diploclinium, Pla: Platycentrum, Rei: Reichenheimia, Tet: Tetraphila. The numbers after the species names indicate Genbank accession numbers. The samples of new species are marked with black stars.