*

Corresponding author: E-mail: bopeng@sinica.edu.tw;

Fax: +886-2-2789-1623.

Begonia pulvinifera (sect. Diploclinium, Begoniaceae), a

new species from limestone areas in Guangxi, China

Ching-I PENG

1,

*, Wai-Chao LEONG

1

, Shin-Ming KU

1,2

, and Yan LIU

3

1

Herbarium (HAST), Research Center for Biodiversity, Academia Sinica, Nangang, Taipei 115, TAIWAN

2

Department of Life Sciences, National Cheng-Kung University, Tainan 701, TAIWAN

3

Guangxi Institute of Botany, Guangxi Zhuangzu Autonomous Region and the Chinese Academy of Sciences, Guilin

3410006, China

(Received June 6, 2005; Accepted May 16, 2006)

ABSTRACT.

Begonia pulvinifera, a new species of sect. Diploclinium from limestone areas in southwestern

Guangxi Zhuangzu Autonomous Region, China, is described and illustrated. This new species is unique in

having pulvinate petioles, a feature not known in any other species of Begonia in China. Begonia pulvinifera

is similar to B. wangii T. T. Yu, differing in the lower surface of the leaf being pale green; petiole with

a reddish brown swollen base; tepals obtuse; tepals of staminate flowers 4; tepals of carpellate flowers 3

and ovary with axile placentation throughout. Begonia pulvinifera also resembles B. cavaleriei Lev., but is

distinguishable by the narrower leaf; pulvinate petiole; stipules triangular with apex acuminate or cuspidate;

and ovate bracts with apex acute or acuminate. Begonia pulvinifera is rare, currently known only from one

population near the border of China and Vietnam.

Keywords: Begonia pulvinifera; Begonia wangii; Begonia cavaleriei; Begoniaceae; China; Guangxi;

Limestone flora; New species; Rare species; sect. Diploclinium; Taxonomy.

INTRODUCTION

While preparing an account of Begoniaceae for the

Flora of China, the senior author made a number of

botanical inventories in the karst areas in Guangxi, China.

Field surveys in these poorly explored areas proved

to be rewarding: 12 new taxa of Begonia, all of sect.

Coelocentrum, were reported in recent years (Fang et al.,

2006; Ku et al., 2004, 2006; Liu et al., 2005; Peng et al.,

2005a, b). In this paper, we report the discovery of a new

species in Begonia sect. Diploclinium from the limestone

areas in southwestern Guangxi, China, which is the

distribution center of the Asiatic sect. Coelocentrum (Shui

et al., 2002). In aspect this new taxon bears a superficial

resemblance to B. wangii T. T. Y u an d B. cavaleriei

H. Lev., but a careful study of the plants grown in the

experimental greenhouse reveals its distinct identity.

DESCRIPTION

Begonia pulvinifera C.-I Peng & Yan Liu, sp. nov. (sect.

Diploclinium)

¡X

TYPE: CHINA, Guangxi Zhuangzu

Autonomous Region, Baise Shi, Jingxi Xian, Huren

Zhen, at base of a limestone hill in broadleaf forest, on

rock face, 22¢X59¡¦19"N, 106¢X40¡¦53"E, elev. 320 m, 26

May 2004, specimens pressed from cultivated plants on

5 Feb 2005, Ching-I Peng 19741-A (holotype, HAST;

isotype, IBK).

Figures 1, 2

Haec species similis Begoniae wangii T. T. Yu, sed a

qua differt foliis subtus pallido-viridibus, petiolis pulvinis,

tepalis obtusis, floribus masculis tepalis 4 instructis,

eis femineis tepalis 3 instructis, placentatione omnino

axili; etiam similis Begoniae cavaleriei Levl., sed a qua

differt foliis angustioribus, petiolis pulvinis, stipulis

triangularibus, apice acuminatis vel cuspidatis.

Herbs, perennial, acaulescent, monoecious. Rhizomes

elongate creeping, to 2 cm thick, glabrous, nodes dense;

stipules triangular, 2.8-3 cm long, 1.7-1.9 cm wide,

TAxONOmy

Botanical Studies (2006) 47: 319-327.

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Botanical Studies, Vol. 47, 2006

Figure 1. Begonia pulvinifera C.-I Peng & Yan Liu. A, Habit; B, Portion of petiole; C, Stipule; D, Bract; E, Staminate flower; F, An-

droecium; G, G¡¦, Stamen; H, Carpellate flower; I, Style branches; J, Ovary, cross section; K, Capsule. All from greenhouse grown

plants of Peng 19741 (type collection, HAST).

PENG et al. ¡X

Begonia pulvinifera,

a new species from Guangxi, China

321

Figure 2. Begonia pulvinifera C.-I Peng & Yan Liu. A, Habit and habitat on limestone rocky slope; B, Cultivated plant at anthesis; C,

Portion of plant, showing rhizome and lower part of the pulvinate petiole; D, Stipules; E, Leaf abaxial surface; F, Inflorescence; G,

Carpellate flower, side view; H, Carpellate flower, adaxial view; I, Capsule, side view; J, Ovary, middle-cross section, showing three

locules each with a bifid placentation. All from Peng 19741 (HAST, type collection).

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glabrous, margin entire, apex acuminate or cuspidate,

persistent. Leaves alternate, arising from rhizome; petiole

greenish, to 24 cm long, 4.5-5 mm in diam., glabrous,

base reddish brown, swollen; leaf blade green, peltate,

ovate, slightly asymmetric, 14-21 cm long, 8-14 cm wide,

glabrous, base rotund, margin entire or nearly so, apex

acuminate, shortly caudate; venation palmate, nerves 9.

Inflorescences axillary, cymose, taller than leaves, 17-45

cm long; peduncle pale green, reddish brown toward base,

34-37 cm long, 3-4 mm across, glabrous; bracts reddish

brown, narrowly ovate, 2-2.5 cm long, 0.9-1.2 cm wide,

glabrous, margin entire, apex acute to acuminate; with

12-14 staminate flowers and 2-4 pistillate flowers. Tepals

pinkish, glabrous. Staminate flowers: pedicel reddish

or greenish, tinged pinkish near junction with tepals,

glabrous, 2.2-3.5(-4.8) cm long; tepals 4, outer 2 tepals

broadly ovate, 2.3-2.8 cm long, 2.2-2.5 cm wide, base

cordate, apex obtuse, inner 2 tepals oblanceolate, 1.6-1.8

cm long, 0.5-0.8 cm wide, apex obtuse; androecium

actinomorphic, very slightly compressed, 5-6 mm tall,

6-9 mm across; stamens more than 100, yellow, filaments

nearly free, 3-5 mm long, anthers obovoid, ca. 1 mm

long, apex truncate or sub-emarginate. Carpellate flowers:

pedicel reddish or greenish, tinged pinkish toward

junction with flower, glabrous, 13-15 mm long; tepals 3,

unequal, outer 2 tepals depressed ovate, 1.8-2 cm long,

2.4-2.6 cm wide, base cordate, apex obtuse, inner 1 tepal

oblanceolate, 1.2-1.4 cm long, 4-5 mm wide; ovary

greenish, tinged reddish, trigonous, unequally 3-winged,

glabrous, 3-locular; placentae axile, bilamellate, styles 3,

4-4.5 mm long, fused at base; stigmas 2-cleft, in a spiraled

band. Infructescences 17 to 45 cm long; capsules nodding,

ca. 3.1 cm long, unequally 3-winged, abaxial wing lunate,

5 mm tall, as wide as capsule, lateral wings smaller, 2-3.5

mm tall. Seed numerous, 0.47-0.57 mm long, 0.25-0.3

mm across, chalazal end rotund or nearly flat; operculum

obtuse to subtruncate.

Distribution. Known only from one population in

Huren Zhen (Township), Jingxi Xien, Baise City, Guangxi

Zhuangzu Autonomous Region, China; at elevation 320 m

(Figure 3).

Etymology. The specific epithet is derived from the

petioles being pulvinate.

Notes. Begonia pulvinifera is unique in having

pulvinate petioles, a feature not known in any other

species of Begonia in China. It resembles B. cavaleriei

(Figure 4), but is distinguishable by the stipules triangular

with the apex acuminate or cuspidate (vs. broadly ovate

to reniform, apex emarginated or acute and awned);

relatively narrower leaf blade; petiole pulvinate; and

bracts ovate with apex acute or acuminate (vs. reniform

to fan-shaped with apex emarginate). Begonia pulvinifera

is also similar to B. wangii T. T. Yu (Figure 5), differing

in the lower surface of the leaf being pale green; petiole

with a reddish brown swollen base; tepals obtuse; tepals

of staminate flowers 4; tepals of carpellate flowers 3 and

ovary with axile placentation throughout. By contrast, in

B. wangii, the lower surface of the leaf is red throughout;

petiole not swollen at base; both staminate and carpellate

flowers with only 2 tepals and apex of tepals acute; and

with parietal placentae near the summit of ovary (Figure

5-I; see also Shui et al., 2002). All three species occur

on the face of limestone rocks, with B. pulvinifera being

the rarest. It is currently known from only one population

in southwestern Guangxi, near the border of China and

Vietnam. The three species appear to form a closely knit,

natural group in sect. Diploclinium, which is recognizable

by the acaulescent habit, peltate leaf, trigonous-cylindrical

ovary and the lunate abaxial wing on the capsule. A

comparison of the salient features of the three species is

shown in Table 1.

Acknowledgements. We thank David E. Boufford (A/

GH) for improving the manuscript; Qiner Yang (PE)

for assistance with the Latin diagnosis; Ya-Wen Hsueh

(HAST) for the line drawings; Tung-Yu Hsieh (HAST)

for preparing seed SEM microphotographs of Begonia

pulvinifera; Chien-I Huang (HAST) for field assistance;

Mao-Lun Weng and Huan-Yu Chen (HAST) for some of

the colored photographs. This study was supported in part

by a grant from the Guangxi Natural Science Foundation

to Yan Liu (IBK) and grants from the Research Center for

Biodiversity, Academia Sinica, Taipei to Ching-I Peng

(HAST).

LITERATURE CITED

Fang, D., S.M. Ku, Y.G. Wei, D.H. Qin, and C.-I Peng. 2006.

Three new taxa of Begonia (sect. Coelocentrum, Begonia-

ceae) from limestone areas in Guangxi, China. Bot. Stud.

47: 97-110.

Figure 3. Distribution of Begonia pulvinifera (¡¹) in Guangxi

Zhuangzu Autonomous Region, China.

PENG et al. ¡X

Begonia pulvinifera,

a new species from Guangxi, China

323

Figure 4. Begonia cavaleriei H. Lev. A, Habit and habitat on limestone rocky slope; B, Portion of a plant, showing green abaxial

leaf surface and a capsule; C, Cultivated plant at anthesis; D, Stipules; E, Inflorescence, side view; F, Inflorescence, adaxial view; G,

Capsule, side view; H, Ovary, cross section (middle part), showing three locules each with a bifid placentation; I, Ovary, middle-cross

section, showing three locules each with a bifid placentation. All but A from Peng 18802 (HAST); A from Peng 20555 (HAST).

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Botanical Studies, Vol. 47, 2006

Figure 5. Begonia wangii T. T. Yu. A, Cultivated plant at anthesis; B, Habit and habitat, showing leaf with green upper surface and

red lower surface; C, Portion of plant, showing rhizome and lower part of the petiole; D, Stipules; E, Inflorescence with staminate

flowers; F, Carpellate flower; G, Capsule, side view; H, Ovary, cross section (middle part), showing three locules each with a bifid pla-

centation; I, Ovary, cross section (near summit), showing parietal placentation. All from Leong 3346 (HAST).

PENG et al. ¡X

Begonia pulvinifera,

a new species from Guangxi, China

325

Figure 6. Begonia seed SEM microphotographs. A-D, Begonia pulvinifera; E-H, B. cavaleriei; I-L, B. wangii. A, E, I, Side view; B, F,

J, View of micropylar end, showing operculum; C, G, K, View of chalazal end; D, H, L, Collar cells, enlarged to show surface sculp-

ture. Arrow indicates the manifestly channeled anticlinal walls between collar cells and operculum. (A-D from Peng et al. 19741.

E-H from Peng et al. 18802. I-L from Leong et al. 3346. All at HAST).

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Botanical Studies, Vol. 47, 2006

Ku, S.M., C.-I Peng, and Y. Liu. 2004. Notes on Begonia (sect.

Coelocentrum, Begoniaceae) from Guangxi, China, with

the report of two new species. Bot. Bull. Acad. S in. 45:

353-367.

Ku, S.M., Y. Liu, and C.-I Peng. 2006. Four new species of Be-

gonia sect. Coelocentrum (Begoniaceae) from limestone

areas in Guangxi, China. Bot. Stud. 47: 207-222.

Liu, Y., S.M. Ku, and C.-I Peng. 2005. Begonia picturata (sect.

Coelocentrum, Begoniaceae), a new species from limestone

areas in Guangxi, China. Bot. Bull. Acad. Sin. 46: 367-376.

Peng, C.-I, Y.M. Shui, Y. Liu, and S.M. Ku. 2005a. Begonia

Table 1. Comparison of Begonia cavaleriei, B. pulvinifera and B. wangii.

B. pulvinifera (Figures 1, 2) B. cavaleriei (Figure 4)

B. wangii (Figure 5)

Stipule

Triangular, apex acuminate or

cuspidate

Broadly ovate to reniform, apex

emarginate or obtuse, awned

Triangular, apex

acuminate or cuspidate

Leaf blade

Color

Abaxially pale green

Abaxially pale green

Abaxially red

Size

14-21 ¡Ñ 8-14 cm

8-22 ¡Ñ 5-19 cm

7-20 ¡Ñ 3-11 cm

Length/width ratio

1.49-1.75

1.16-1.89

1.82-2.44

Petiole

Swollen at base

Not swollen

Not swollen

Bract

Ovate, apex acute to

acuminate

Reniform to fan-shaped, apex

emarginate

Ovate, apex acuminate

Staminate flower

Tepal number

4

4

2

Tepal apex

Obtuse

Obtuse

Acute

Outer tepal

2, broadly ovate

2, broadly ovate to ovate

2, broadly ovate to oblate-

orbicular

Inner tepal

2, oblanceolate

2, oblong

lacking

Carpellate flower

Tepal number

3

3

2

Tepal apex

Obtuse

Obtuse

Acute

Outer tepals

2, depressed ovate

2, broadly ovate or suborbicular 2, orbicular-ovate

Inner tepal

1, oblanceolate

1, oblong

lacking

Placentation

Middle part of ovary

Axile

Axile

Axile (Figure 5-H)

Apical part of ovary Axile

Axile

Parietal (Figure 5-I)

Seed (Figure 6)

Length (mm)

0.47-0.57

0.4-0.48

0.48-0.6

Anticlinal walls between

collar cells and operculum

Not channeled

Not channeled

Manifestly channeled

(Figure 6-J)

fangii (sect. Coelocentrum, Begoniaceae), a new species

from limestone areas in Guangxi, China. Bot. Bull. Acad.

Sin. 46: 83-89.

Peng, C.-I, S.M. Ku,

and W.C. Leong. 2005b. Begonia liuyanii

(s ect. Coelocentrum, Begoniaceae), a new species from

limestone areas in Guangxi, China. Bot. Bull. Acad. Sin.

46: 245-254.

S hui, Y.M., C.-I P eng, and C.Y. Wu. 2002. S ynops is of the

Chinese species of Begonia ( Be gon ia ce a e), wit h a

reappraisal of sectional delimitation. Bot. Bull. Acad. Sin.

43: 313-327.

PENG et al. ¡X

Begonia pulvinifera,

a new species from Guangxi, China

327