*
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, 22X5919"N, 106X4053"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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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).
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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 () in Guangxi
Zhuangzu Autonomous Region, China.
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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).
pg_0006
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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).
pg_0007
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 8-14 cm
8-22 5-19 cm
7-20 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.
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Begonia pulvinifera,
a new species from Guangxi, China
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