全 文 ：
Guihaia Jan. 2016，36 (1)： 73-82
http://journal.gxzw.gxib.cn
http://www.guihaia-journal.com


DOI： 10.11931/guihaia.gxzw201512003
董莉娜，刘演，曹小燕. 国产秋海棠属（秋海棠科）花粉形态及其分类学意义［J］. 广西植物，2016，36(1)：73-82
DONG LN，LIU Y，CAO XY. Pollen morphology of Chinese Begonia (Begoniaceae) and its taxonomical significance［J］. Guihaia，2016，36(1)：73-82

Pollen morphology of Chinese Begonia (Begoniaceae)
and its taxonomical significance

DONG Li-Na*， LIU Yan， CAO Xiao-Yan

( Guangxi Key Laboratory of Plant Conservation and Restoration Ecology in Karst Terrain，Guangxi Institute of Botany，
Guangxi Zhuang Autonomous Region and Chinese Academy of Sciences， Guilin 541006， China )

Abstract： Begonia L. is the sixth biggest genus of flowering plants in the world and a major genus in the family
Begoniaceae. It is complicated in current section delimitation and more morphological characters are needed for
critical revaluation within the genus. In present study，we selected 21 species from sections Coelocentrum，
Begonia，Platycentrum and Reichenheimia of Begonia mainly distributed in China. Using the method of scanning
electron microscopy (SEM)，the pollen morphology was carefully examined and its systematic significance was
discussed. The results showed that the common palynological characters of studies taxa were exhibited as monads，
radially symmetrical，isopolar，3-zono-colporate and perprolate to prolate. For non-metric multidimensional scaling
(NMDS) analysis，nine stable pollen characters were selected and coded as unordered and unweighted. The results
supported that these sections were not monophyletic groups and the useful palynological features for this study
were the pollen sides，outline of the poles，colpus，exine ornamentation，and margo. According to the
ornamentation of margo，the studied taxa can be divided into two groups：(A) without margo and psilate margo，
(B) regulate，exquisitely regulate and coarsely regulate margo. In relation to Group B，the taxa with regulate and
exquisitely regulate grains were gathered while the taxa with coarsely regulate margo were located between Group
A and B. It indicated that the feature of margo was exhibited as a transition，from without margo and psilate
margo，along coarsely regulate margo to exquisitely regulate. Therefore，it is worthy to pay more attention on the
feature of margo and increase more taxa of the genus in further studies.
Keywords： SEM，characters coded，NMDS，margo，non-monophyletic groups
CLC number： 949.759.7 Document code： A Article ID： 1000-3142(2016)01-0073-10

国产秋海棠属（秋海棠科）花粉形态及其分类学意义
董莉娜*，刘 演，曹小燕
（ 1. 广西喀斯特植物保育与恢复生态学重点实验室， 广西植物研究所，广西 桂林 541006 ）

摘 要：秋海棠属是世界有花植物第六大属，是被子植物分类困难的类群之一，亟需增加形态性状的比
较研究，以便于今后对该属开展分类学修订。该研究选取国产秋海棠属中较为常见的侧膜组、秋海棠组、
单座组和二室组共 21 种，应用扫描电镜观察花粉微形态，探讨花粉形态对秋海棠属植物的分类学意义。

收稿日期：2015-12-02 修回日期：2016-01-18
基金项目：广西自然科学基金（2014GXNSFBA118076）；广西植物研究所基本业务费（14001）；广西喀斯特植物保育与恢复生态学重点实验室开
放基金（GKB15-A-12）[Supported by the Natural Science Foundation of Guangxi(2014GXNSFBA118076); Fundamental Research Fund of Guangxi Institute
of Botany (14001); Guangxi Open Fund For Key Laboratory of Plant Conservation and Restoration Ecology in Karst Terrain (GKB15-A-12)]。
作者简介：董莉娜（1979-），女，陕西宝鸡人，博士，助理研究员，主要研究方向为喀斯特地区特有类群的分类与系统，(E-mail)donglina@gxib.cn。
*通讯作者
广西壮族自治区
中 国 科 学 院
74 广 西 植 物 36 卷


结果表明：秋海棠属植物的花粉多为单粒花粉，辐射对称，等极，三孔沟，超长球形到长球形。选取 9
个稳定的花粉特征进行无序和不加权的性状编码，应用非线性多维标度分析对花粉特征矩阵进行聚类分
析，结果支持这些组都不是单系类群需要重新修订，其中花粉边缘形状、极面观轮廓、萌发沟和花粉的
外壁纹饰具有一定分类学意义，特别是塞缘特征具有重要的分类意义。根据塞缘特征可以将研究类群区
分为 2 个类群：（A）无塞缘或塞缘光滑；（B）塞缘颗粒状。类群 B 中具规则颗粒状和精细颗粒状塞
缘的种类聚在一起，而具粗糙颗粒状塞缘的种类位于类群 A 和 B 的中间，很可能是 2 个类群的过渡性状，
这需要增加取样做进一步的研究。
关键词：扫描电镜，性状编码，非线性多维标度分析，塞缘，非单系类群

Begonia L. is estimated to have more than 1900 named
species (Twyford et al，2015)，comprising nearly all the
species of Begoniaceae (Forrest & Hollingsworth，2003).
The genus widely distributed in tropical and subtropical
areas excluding Australia，within which most species occur
as localized endemics in moist，shaded，forest or limestone
habitats. This genus can be easily distinguished by their
monoecious perennials，mostly fleshy stems，usually
asymmetric leaf shape，numerous centripetal stamens，
twisted stigma，numerous seeds and possess collar cells
below an operculum of the seed.
Begonia has a complicated taxonomic history ，
especially in the delimitation of sections (Shui et al，2002).
Traditionally，the floral and fruit characteristics are used for
sectional distinctions，such as perianth number，style
number and morphology ， locule number ， placentae
number，and mode of fruit dehiscence (Doorenbos et al，
1998；Shui et al，2002；Gu et al，2009). In the light of
recently molecular phylogeny (Forrest et al，2005)，the
current infrageneric classification has a certain diagnostic，
but only poor predictive value within Begonia (Thomas et
al，2011). It is necessary to careful study of more qualitative
characters for critical revaluation within the genus.
Pollen grains are often of valuable assistance in
delimiting taxonomic relationships imply useful characters
for delimiting sections and species in Begonia. Van den
Berg (1984) collected nearly all known African species of
Begonia and found that pollen size，outline of the poles，and
margo can provide significant information for the
classification. Rajbhandary et al (2012) studied 28 species
from Nepal and suggested that margo could be delimited
section Platycentrum from all other sections. However，
palynological studies are deficient in this massive genus，
especially in China. Hence，we carefully describe pollen
morphology of main sections of Begonia in China and
discuss their taxonomical significance.
1 Materials and Methods
The species of Begonia has strikingly morphological
variation and exceedingly endemism in China. Shui et al
(2002) recognized 150 species and divided into nine
sections. Gu et al (2009) divided 173 species into seven
sections. With relation to these sections，the species-rich
sections are commonly adopted，e.g. Coelocentrum，
Begonia，Platycentrum and Reichenheimia. We selected 21
species from these sections based on Gu’s (2009)
classification (Table 1). The herbarium specimens collected
in China and deposited in KUN，IBK，and IBSC.
Mature male flowers were selected from herbarium
collections. Pollen grains were mounted on the stubs，coated
with gold in a sputter coater，and observed with a Hitachi
S-4800 scanning electron microscope at 10 kV. The pollen
size was measured on photo of SEM by the software Image
J and the mean was calculated using SPSS 22. Terminology
for pollen morphology is taken from Van den Berg (1984)
and Punt et al (2007).
The stable characters were selected and coded for
NMDS (Non-metric multidimensional scaling) analysis.
Some characters were excluded due to the directed
correlation between each other. For example，the pollen
shape was exhibited as pointed and rounded. Casually，
when the colpi were elongated and closely approached each
other in the poles，the pollen was pointed. The colpi were
normal，meanwhile the pollen was rounded. In this case，
we selected one of these characters for NMDS analysis.
Totally，nine pollen characters were selected and coded as
unordered and unweighted (Table 3，4).
1 期 董莉娜等：国产秋海棠属（秋海棠科）花粉形态及其分类学意义 75


Table 1 Materials examined among Chinese begonias species
Taxa World distribution China distribution
Classification
Voucher
Shui et al，2002 Gu et al，2009
Begonia. alveolata T. T. Yu China，Vietnam Yunnan Diploclimium Begonia Y. M. Shui，B91-527 (KUN)
B. baviensis Gagnepain China，Vietnam Guangxi，Yunnan Platycentrum Platycentrum S. Q. Chen，4980 (IBSC)
B. edulis H. Léveillé China，Vietnam Guangdong，Guangxi Platycentrum Platycentrum Z. T. Li，601930 (IBK)
B. fangii Y. M. Shui &
C.I. Peng
China Guangxi Coelocentrum Coelocentrum Y. K. Li，00095 (IBK)
B. fimbristipula Hance China S China Diploclinium Begonia Z. Huang，31018 (IBK)
B. grandis Dryander China Widely Diploclinium Begonia J. X. Zhong，83487 (IBK)
B. hemsleyana J. D. Hooker China，Vietnam Guangxi，Yunnan Platycentrum Platycentrum Z. T. Li，602381 (IBK)
B. henryi Hemsley China S China Reichenheimia Reichenheimia S. W. Deng，90840 (IBK)
B. labordei H. Léveillé China Guizhou，Sichuan，
Yunnan
Diploclinium Begonia s. n.，50763 (IBK)
B. lanternaria Irmscher China，Vietnam Guangxi Coelocentrum Coelocentrum Nonggang Expedition，10694
(IBK)
B. leprosa Hance China Guangdong，
Guangxi
Leprosae Begonia Z. X. Zhang & S. Z. Wang，
4103 (IBK)
B. lipingensis Irmscher China Guangxi，Guangdong，
Hunan
Platycentrum Platycentrum J. F. Qin & Z. T. Li，70904
(IBK)
B. luzhaiensis T. C. Ku China Guangxi Coelocentrum Coelocentrum Z. Z. Chen，53128 (IBK)
B. mengtzeana Irmscher China Yunnan Platycentrum Platycentrum X. W. Li，338 (KUN)
B. ornithophylla Irmscher China Guangxi Coelocentrum Coelocentrum Nonggang Expedition，12062
(IBK)
B. parvula H. Léveillé &
Vaniot
China Guizhou，Yunnan Reichenheimia Reichenheimia M. K. Li，00011 (IBSC)
B. pedatifida H. Léveillé China S China Platycentrum Platycentrum Z.Z. Chen，51847 (IBK)
B. polytricha C. Y. Wu China Yunnan Platycentrum Platycentrum S. K. Wu，50736 (KUN)
B. setifolia Irmscher China Yunnan Diploclinium Begonia X. R. Liang，68135 (IBK)
B. taliensis Gagnepain China Yunnan Diploclinium Begonia R. C. Qin，24680 (KUN)
B. wilsonii Gagnepain China Chongqing，Sichuan Reichenheimia Reichenheimia X. L. Jiang & X. B. Zhang，
31964 (IBK)

The NMDS plot was constructed with the PAST 1.81
software package (Hammer et al，2007). The NMDS plot is
accurately reflect the actual distances among the studied
samples when stress index is between 0.05 and 0.2 (Clarke
& Warwick，1994；Lu et al，2010). Correlation similarity
index was a lower stress (0.1954) index than any other
index available in the program，suggesting that the NMDS
plot is reliable and can be used for this analysis.
2 Results and Analysis
2.1 General description of pollen morphology
Pollen grains of all studied taxa are monads，radially
symmetrical，isopolar，and 3-zono-colporate. The main
variation exhibits in size，shape，colpus，and exine
ornamentation (Table 2，Plates 1-3). The further variable
characters are the occurrence of margo along the colpus.
2.1.1 Pollen size and shape The mean size shows a
variance of ± 1－4 μm in polar axis. The biggest variance is
found in B. ornithophylla with measurement ranged from
18.2 μm × 8.4 μm to 24.5 μm × 10.9 μm. Excluding B.
ornithophylla，all examined pollen rang from 16.4－
23.8 μm in polar axis and 7.6－10.7 μm in equatorial axis.
B. edulis has the smallest pollen，16.4 μm × 8.6 μm. For
NMDS analysis，we employ polar axis to represent pollen
size and divided into two categories，as mean values in μm：
(1) small (≤ 20 μm) and (2) medium (> 20 μm).
Pollen shape are mainly exhibited as perprolate (P/E>
2.00) in studied taxa. The prolate grains (P/E：1.33－2.00)
are discovered in B. edulis，B. fangii and B. lanternaria.
These grains are nearly perprolate by having the P/E ratio
around 1.9－2.0. The outline of the grains being always
more or less elliptical，the sides are usually straight in most
taxa. Some taxa are characterized by concave sides in sect.
Begonia [B. alveolata (Plate 2:1)，B. fimbristipula (Plate
3:4)，B. labordei (Plate 2:3)，B. leprosa (Plate 3:13)，
76 广 西 植 物 36 卷


Table 2 Characters of the pollen morphology of the examined Begonia
Taxa
Polar
axis
(μm)
Equatorial
axis
(μm)
P/E
ratio Shape Side
Outline of
poles
Colpus
Exine ornamentation
Equatorial
view
Polar
view
Equtorial
view Polar view Margo
Begonia
alveolata
18.7±1.2 8.5±0.7 2.2 Perprolate Concave Rounded Linear，
sunken
Approached Coarsely
striate
Striato-
reticulate，
perforate
Absent
B. baviensis 17.8±1.3 8.3±0.2 2.1 Perprolate Straight Rounded Boatshaped，
retuse
Approached Finely
striate
Striate Absent
B. edulis 16.4±0.9 8.6±0.3 1.9 Prolate Convex Rounded Boatshaped，
retuse
Approached Coarsely
striate
Striato-
reticulate，
perforate
Thicken and
psilate
B. fangii 18.9±0.1 9.8±0.0 1.9 Prolate Convex Pointed Boatshaped，
retuse
Closely
approached
Coarsely
striate
Striato-
reticulate，
perforate
Coarsely
regulate，
perforate
B. fimbristipula 20.8±0.3 8.1±0.1 2.6 Perprolate Concave Pointed Boatshaped，
sunken
Closely
approached
Coarsely
striate
Striato-
reticulate，
perforate
Exquisitely
regulate，
perforate
B. grandis 23.4±1.7 10.1±0.6 2.3 Perprolate Straight Rounded Boatshaped，
retuse
Approached Finely
striate
Striato-
reticulate，
perforate
Exquisitely
regulate，
perforate
B. hemsleyana 18.6±0.8 8.2±0.4 2.3 Perprolate Straight Rounded Boatshaped，
sunken
Approached Coarsely
striate
Striate，
perforate
Absent
B. henryi 25.1±0.1 9.9±0.3 2.5 Perprolate Striaight Rounded Linear，
sunken
Closely
approached
Finely
striate
Striato-
reticulate，
perforate
Exquisitely
regulate，
perforate
B. labordei 22.2±0.8 8.8±0.1 2.5 Perprolate Concave Rounded Linear，
sunken
Approached Coarsely
striate
Striato-reti
culate，
perforate
Regulate，
perforate
B. lanternaria 21.2±2.6 10.7±0.4 2.0 Prolate Concave Pointed Boatshaped，
retuse
Closely
approached
Finely
striate
Striato-
reticulate，
perforate
Thicken and
psilate，
perforate
B. leprosa 23.7±0.6 10.3±0.4 2.3 Perprolate Concave Rounded Boatshaped，
retuse
Approached Coarsely
striate
Striato-
reticulate，
perforate
Psilate，
perforate
B. lipingensis 18.3±1.8 7.6±0.2 2.4 Perprolate Straight Rounded Boatshaped，
retuse
Approached Finely
striate
Striate，
perforate
Thicken and
psilate
B. luzhaiensis 22.0±0.1 9.4±0.0 2.3 Perprolate Concave Rounded Linear，
sunken
Approached Coarsely
striate
Striato-
reticulate，
perforate
Regulate，
perforate
B. mengtzeana 21.6±0.6 9.3±0.6 2.3 Perprolate Straight Rounded Linear，
sunken
Approached Coarsely
striate
Striate，
perforate
Regulate，
perforate
B. ornithophylla 21.4±4.4 9.7±1.8 2.2 Perprolate Straight Pointed Boatshaped，
sunken
Closely
approached
Coarsely
striate
Striato-
reticulate，
perforate
Coarsely
regulate，
perforate
B. parvula 23.8±0.4 9.0±0.4 2.6 Perprolate Straight Pointed Linear，
sunken
Closely
approached
Coarsely
striate
Striato-
reticulate，
perforate
Exquisitely
regulate，
perforate
B. pedatifida 21.1±0.3 8.3±0.1 2.5 Perprolate Straight Pointed Boatshaped，
retuse
Closely
approached
Finely
striate
Striate，
perforate
Thicken and
psilate
B. polytricha 18.8±0.5 8.8±0.3 2.1 Perprolate Convex Rounded Boatshaped，
retuse
Approached Coarely
striate
Striato-
reticulate，
perforate
Regulate，
perforate
B. setifolia 22.4±0.0 8.5±0.3 2.6 Perprolate Concave Rounded Boatshaped，
sunken
Approached Finely
striate
Striato-
reticulate，
perforate
Exquisitely
regulate，
perforate
B. taliensis 19.9±2.4 9.0±0.3 2.2 Perprolate Concave Pointed Boatshaped，
retuse
Closely
approached
Finely
striate
Striate，
perforate
Regulate，
perforate
B. wilsonii 23.5±1.2 9.6±0.2 2.4 Perprolate Straight Rounded Boatshaped，
retuse
Approach Corasely
striate
Striato-
reticulate，
perforate
Coarsely
regulate

1 期 董莉娜等：国产秋海棠属（秋海棠科）花粉形态及其分类学意义 77


Table 3 Pollen characters and character states of Begonia
No. Character Character states
1 Size 0：Small (≤20 μm)；
1：Medium (>20 μm)
2 Side 0：Concave； 1：Straight；
2：Convex
3 Outline of poles 0：Rounded； 1：Pointed
4 Shape of colpus 0：Linear； 1：Boatshaped
5 Colpus membrane 0：Sunken； 1：Retuse
6 Equatorial view of exine
ornamentation
0：Coarsely striate；
1：Finely striate
7 Polar view of exine
ornamentation
0：Striato-reticulate；
1：Striate
8 Margo 0：Absent； 1：Present
9 Shape of margo 0：Psilate； 1：Coarsely
regulate； 2：Regulate；
3：Exquisitely regulate

Table 4 Matrix of coded pollen character
states for studied taxa
No. Taxa 1 2 3 4 5 6 7 8 9
1 Begonia
alveolata
0 0 0 0 0 0 0 0 ?
2 B. baviensis 0 1 0 1 1 1 1 0 ?
3 B. edulis 0 2 0 1 1 0 0 1 0
4 B. fangii 0 2 1 1 1 0 0 1 1
5 B. fimbristipula 1 0 1 1 0 0 0 1 3
6 B. grandis 1 1 0 1 1 1 0 1 3
7 B. hemsleyana 0 1 0 1 0 0 1 0 ?
8 B. henryi 1 1 0 0 0 1 0 1 3
9 B. labordei 1 0 0 0 0 0 0 1 2
10 B. lanternaria 1 0 1 1 1 1 0 1 0
11 B. leprosa 1 0 0 1 1 0 0 1 0
12 B. lipingensis 0 1 0 1 1 1 1 1 0
13 B. luzhaiensis 1 0 0 0 0 0 0 1 2
14 B. mengtzeana 1 1 0 0 0 0 1 1 2
15 B. ornithophylla 1 1 1 1 0 0 0 1 1
16 B. parvula 1 1 1 0 0 0 0 1 3
17 B. pedatifida 1 1 1 1 1 1 1 1 0
18 B. polytricha 0 2 0 1 1 0 0 1 2
19 B. setifolia 1 0 0 1 0 1 0 1 3
20 B. taliensis 0 0 1 1 1 1 1 1 2
21 B. wilsonii 1 1 0 1 1 0 0 1 1
Note：Deleted character is coded as ?.

B. setifolia (Plate 1:13)，and B. taliensis (Plate 1:16)] and
in sect. Coelocentrum [B. lanternaria (Plate 1:2) and B.
luzhaiensis (Plate 3:14)]，in which the pollen has obvious
constriction around the ectoaperture. Some pollen is
protruded around the ectoaperture and formed the convex
side，e.g. sect. Platycentrum [B. edulis (Plate 3:2) and B.
polytricha (Plate 3:16)] and Coelocentrum [B. fangii
(Plate 3:3)].
2.1.2 Apertures The apertures are 3-zono-colporate
formed by ectoaperture and endoaperture in studied taxa.
The ectoaperture has three colpi and the endoaperture is
situated at the equator in the colpus. The colpus is
documented by nanograndulate，especially around the
endoaperture. In most taxa，the colpus is broader at the
equator than the polar，named boatshaped. The colpus is
inflxed and formed narrow linear in B. alveolata (Plate
2:1，5，9)，B. henryi，B. luzhaiensis (Plate 3：14，18，
22)，and B. mengtzeana (Plate 2：4，8，12). Sometimes，
the margin of colpus is deeply inflexed lead to the
membrane sunken. In studied taxa ， the colpi are
approached each other at the polar，while in some taxa the
colpi are extremely elongated and approached each other
closely at the poles， e.g. B. fangii (Plate3:7)，B.
fimbristipula (Plate 3:8)，B. henryi，B. lanternaria (Plate
1:6)，B. ornithophylla，B. parvula (Plate 3:19)，B.
pedatifida (Plate 1:8)，and B. taliensis (Plate 1:17).
2.1.3 Exine ornamentation The exine is shown a
regular pattern of approximately parallel muri，defined
as striate. Depending on the width of lirae and striae，
the striate pattern can be designated as finely or
coarsely striate. The finely striate owned more than ten
straight and long lirae on each mesocolpia (Plate 1).
The exine ornamentation is defined as coarsely striate
by having short and less than ten lirae on each
mesocolpia (Plates 2，3).
The striate pattern is sometimes replaced by
irregular ornamentation，especially towards the poles.
Often perforate are intensively emerged on the poles，
resulting in a fuzzy striato-reticulate appearance in
most taxa，while the striate is exhibited in B. baviensis
(Plate 1:5)，B. hemsleyana (Plate 2:6)，B. lipingensis
(Plate 1:7)，B. mengtzeana (Plate 2:8)，B. pedatifida
(Plate 1:8)，and B. taliensis (Plate 1:17).
A striking feature is the presence of a margo：a
zone along the ectocolpus showing a deviating
78 广 西 植 物 36 卷





Plate 1 Pollen with finely striate on the surface 1，5，9. B. baviensis； 2，6，10. B. lanternaria； 3，7，11. B. lipingensis； 4，8，12. B. pedatifida；
13-15. B. setifolia； 16-18. B. taliensis. Scale bars：10 μm in equatorial view and polar view，2 μm in higher magnification of margo. The same below..
.
ornamentation from the remainder of the mesocolpium.
The margo can be divided into four different types based
on different ornamentation. (i) The margo is psilate and
found in B. edulis (Plate 3:10)，B. lanternaria (Plate
1:10)，B. leprosa (Plate 3:21)，B. lipingensis (Plate 1:11)，
and B. pedatifida (Plate 1:12). (ii) The margo is coarsely
regulate and discovered in B. fangii (Plate 3:11)，B.
ornithophylla，and B. wilsonii (Plate 3:9). (iii) The margo is
regulate，viz. B. labordei (Plate 2:11)，B. luzhaiensis (Plate
3:22)，B. mengtzeana (Plate 2:12)，B. polytricha (Plate
3:24)，and B. taliensis (Plate 1:18). (iv) The margo is
exquisitely regulate，e.g. B. fimbristipula (Plate 3:12)，B.
grandis，B. henryi，and B. parvula (Plate 3:23).
2.2 NMDS analysis
The studied species formed a domain near x axis in
quadrant I and IV (Plate 4). In the domain，all studied
sections are included：three species from section Begonia (B.
fimbristipula，B. labordei，and B. setifolia)，one species
from section Platycentrum (B. mengtzeana)，one species
from section Coelocentrum (B. luzhaiensis)，and two
1 期 董莉娜等：国产秋海棠属（秋海棠科）花粉形态及其分类学意义 79





Plate 2 Pollen with coarsely striate on the surface 1，5，9. B. alveolata； 2，6，10. B. hemsleyana；
3，7，11. B. labordei； 4，8，12. B. mengtzeana.

species from section Reichenheimia (B. henryi and B.
parvula). The remainder species are scattered in all
quadrants. In section Begonia，B. alveolata and B. leprosa
are scattered in quadrant III，while B. taliensis is located in
quadrant I. The rest species of section Platycentrum are
mainly located in quadrant II except for B. pedatifida in
quadrant III and B. polytricha in quadrant I. Within studied
species of section Coelocentrum，three species are dispersed
out of the domain and located in quadrant II (B. fangii)，III
(B. lanternaria) and IV (B. ornithophylla). B. wilsonii is
separated from the domain of section Reichenheimia and
located near y axis in quadrant III.
All studied taxa are divided into two groups according
to the character of margo. Group A is included the taxa with
psilate margo [B. edulis (Plate 3:10)，B. lanternaria (Plate
1:10)，B. leprosa (Plate 3:21)，B. lipingensis (Plate 1:11)，
and B. pedatifida (Plate 1:12)) or without margo (B.
alveolata (Plate 2:9)，B. baviensis (Plate 1:9)，and B.
hemsleyana (Plate 2:10)]. Group B is exhibited with
regulate margo. Within these taxa，regulate and exquisitely
regulate margo are gathered together in the domain. B.
polytricha (Plate 3:24) and B. taliensis (Plate 1:18) is
locatted around the domain by having small pollen and
regulate margo. While，the coarsely regulate margo is
scattered between Group A and the domain in Group B，viz.
B. fangii (Plate 3:11)，B. ornithophylla，and B. wilsonii
(Plate 3:9).
3 Discussion
Morphological and anatomical fruit and ovary
characters have traditionally played an essential role as
diagnostic characters and for infrageneric delimitation in
Begonia (Irmscher，1925；Warburg，1894；Doorenbos et
al，1998). However，these characters were identified as
highly homoplasious and had been overestimated in the past
(Matolweni et al，2000；Forrest et al，2003；Forrest et al，
2005；Neale et al，2006；Thomas et al，2011). Pollen
morphology should be to unearth the taxonomy of Begonia
(Van den Berg，1984).
The palynological characters of 21 studied taxa have
common synapomorphy in Begonia，such as monads，
radially symmetrical，isopolar，and 3-zono-colporate (Van
den Berg，1984；Rajbhandary et al，2012). The variability
80 广 西 植 物 36 卷





Plate 3 Pollen with coarsely striate on the surface 1，5，9. B. Wilsonii； 2，6，10. B. edulis； 3，7，11. B. fangii； 4，8，12：
B. fimbristipula； 13，17，21. B. leprosa； 14，18，22. B. luzhaiensis； 15，19，23. B. parvula； 16，20，24. B. polytricha.

characters are displayed on pollen size，apertures，and exine
ornamentation，especially the appearance of margo along
colpus. The pollen data lend some support to the idea that
the studied sections are not monophyletic and need revised
(Thomas et al，2011；Chung et al，2014). Here，we have
further discussed the taxonomical significance of pollen
characters within the studied taxa of genus Begonia.
Within studied species，the pollen varied from 16.4－
23.8 μm with a variance of ±1－4 μm in polar axis. For easy
to demarcation，the pollen is divided into two
1 期 董莉娜等：国产秋海棠属（秋海棠科）花粉形态及其分类学意义 81





Plate 4 Non-metric multidimensional scaling (NMDS)
plot of nine pollen characters sampled for 21
species of Begonia in China

typesbased on the mean of polar axis：≤ 20 μm and > 20 μm.
In fact，the measurements span the range in some species，
e.g. B. lanternaria，B. ornithophylla，and B. taliensis. In
relation to the different treatment (Reitsma，1969) and
aberrantly 2n pollen (Dewitte et al，2009)，it should be very
careful to take pollen size as recognized characters in the
genus.
The shape is highly similar to the studied taxa，while
the sides are variable at species level. Van den Berg (1984)
found that convex and straight sides imply rounded poles，
while concave grains tend to possess or less pointed poles.
The different situations were observed in this study. The
convex and straight grains exhibited pointed poles in B.
fangii (Plate 3:3，7)，B. ornithophylla，B. parvula (Plate
3:15，19) and B. pedatifida (Plate 1:4，8). The concave grains
exhibited rounded poles in B. alveolata (Plate 2:1，5)，B.
labordei (Plate 2:3，7)，B. leprosa (Plate 3:13，17) and B.
setifolia (Plate 1:13-14). More species are needed to clarify
the correlation between the sides and the outline of the poles.
The feature of aperture is stable as 3-zono-colporate in
Begonia. The main variation is the shape and length of
colpus. In most studied taxa，the colpi are elongated and
approached to each other closely at the poles，especially
within the boatshaped colpus. In relatively rare，the colpi
anastomose at the poles as syncolpate grain (Van den Berg，
1984). In this study，the syncolpate grains is not discovered
but the colpi are elongated and closely approach each other
at the poles and the apocolpium resemble as a point in some
taxa，e.g. B. lipingensis (Plate 1:7)，B. taliensis (Plate 1:17)，
B. fimbristipula (Plate 3:8). The feature of apocolpium can
be used as discrimination at the species level combined with
other characters and has limited classification significance at
the section level.
The striate pollen is the common sculpture on the
surface of the grains within Begonia. Two main types can be
identified as finely and coarsely striate based on the width
of the lirae and striae (Van den Berg，1984；Rajbhandary et
al，2012). Perforate is minute holes situated in the tectum
and common at the polar and in the margo. Especially，in
coarsely striate grains，the sculpture is ornamented as
striato-reticulate due to the sink around single hole at the
poles. Most finely striate pollens are kept as striate at the
poles in the presence of perforate，e.g. B. baviensis (Plate
1:5)，B. lipingensis (Plate 1:7)，B. pedatifida (Plate 1:8)，
and B. taliensis (Plate 1:17). The sculpture is very useful to
identify different species，but it need further discussion
about taxonomical significance at the section level under the
context of recently phylogeny of the genus.
It is worthy to notice that margo，a zone along
ectocolpus showing differentiated from the remainder of the
sexine，the extra characters on the sculpture. Margo was
discovered in Begonia from Africa and Nepal (Van den
Berg，1984，Rajbhandary et al，2012). Rajbhandary et al
(2012) stressed that margo could be used as a distinguished
character for the separates of section Platycentrum from all
other sections of Nepalese Begonia. In relation to China，the
margo is found in all sections of Begonia. Furthermore，the
feature of margo exhibited a clear transition，from without
margo and psilate margo，along coarsely regulate margo to
exquisitely regulate，based on NDMS analysis within this
study. It is important to pay attention on the feature of
margo within Begonia in the future studies.
Acknowledgements We would like to thank REN
Zong-Xin for SEM help and the anonymous reviewer for
the constructive comments on the manuscript. We also
thank the herbaria at Kunming Institute of Botany (KUN)，
Guangxi institute of Botany (IBK)，and South China
82 广 西 植 物 36 卷


Botanical Garden Herbarium (IBSC) for allowing us to
collect pollen samples.
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