Botanical Studies (2008) 49: 167-175.
Corresponding author: E-mail: email@example.com; Tel:
Begonia pengii (sect. Coelocentrum, Begoniaceae), a
new species from limestone areas in Guangxi, China
, Yoshiko KONO
, and Yan LIU
Herbarium (HAST), Research Center for Biodiversity, Academia Sinica, Nangang, Taipei 115, Taiwan
Guangxi Institute of Botany, Guangxi Zhuangzu Autonomous Region and the Chinese Academy of Sciences, Guilin
(Received September 5, 2007; Accepted March 7, 2008)
Begonia pengii, a new species from Guangxi Zhuangzu Autonomous Region, China, is here
described and illustrated. Its somatic chromosome number (2n = 30) and karyotype are reported. Begonia
pengii belongs to sect. Coelocentrum and somewhat resembles B. variifolia Y. M. Shui & W. H. Chen, from
which it differs by its much larger size, leaves (11-)15-27 × (6-)8-15 cm, narrowly ovate, peduncle 17-37 cm;
anther sacs red margined; and capsules 1.8-2.5 cm long. Like most members of sect. Coelocentrum, B. pengii
is an attractive species and is rare, known only from one steep limestone hill in western Guangxi.
Keywords: Begonia luochengensis; Begonia pengii; Begonia picturata; Begonia sect. Coelocentrum; Begonia
variifolia; Begoniaceae; China; Chromosome number; Guangxi; Karyotype; Limestone flora; New species;
The spectacular karst limestone landform in Guangxi,
China is home to many endemic and rare species. As
a result of our continued fieldwork in Guangxi and
research on Begonia, an attractive new species of sect.
Coelocentrum was discovered, which is described below.
MATERIALS AND METHODS
Cryo scanning electron microscopy
Fresh leaves of Begonia pengii were dissected and
attached to a stub. The samples were frozen with liquid
nitrogen slush, then transferred to a sample preparation
chamber at -160°C. After 5 min, when the temperature
rose to -130°C, the samples were fractured. The samples
were etched for 10 min at -85°C. After coating at -130
°C, the samples were transferred to the SEM chamber
and observed at -160°C with a cryo scanning electron
microscope (FEI Quanta 200 SEM/Quorum Cryo System
Root tips of Begonia pengii were pretreated with 2
mM 8-hydroxyquinoline solution at 15-18°C for about 8
h and fixed in ethanol-acetic acid (3:1) at about 4°C for
more than 24 h. Chromosome preparations were made
by the enzyme squash method in an enzyme mixture of
4% Cellulase (Onozuka R-10, Yakult) and 2% Pectolyase
Y-23 (Kyowa Chemical Products) at about 37°C for 1 h.
The preparations were stained with 2% Giemsa solution
(Merck). Classification of the chromosome complements
based on centromere position at mitotic metaphase follows
Levan et al. (1964). The voucher specimen has been
deposited in HAST.
Begonia pengii S. M. Ku & Yan Liu, sp. nov. —TYPE:
CHINA. Guangxi Zhuangzu Autonomous Region,
Bama Xian, Xishan. Sheltered, vertical limestone rock
face, ca. 500 m alt. 18 May 2007, Ching-I Peng, Yan
Liu, Kuo-Fang Chung, Ming-Chao Yu & Hai-Shan
Gao 21070 (holotype: HAST; isotype: IBK).
彭氏秋海棠 Figures 1, 2, 3A
Begoniae variifoliae Y. M. Shui & W. H. Chen affinis,
sed foliis anguste ovatis, antherarum saccis rubro-
marginatis, habitu multo majore [foliis (11-)17-27
× (6-)8.5-15 cm, pedunculis 17-30 cm longis, capsulis
1.8-2.5 cm longis] differt.
Herbs, monoecious, epipetric, perennial, rhizomatous.
Rhizome 6-15 cm or longer, (5-)9-12(-18) mm thick,
internodes (5-)7-10(-12) mm long, brown or reddish
brown, villous near base of petiole and leaf scars. Stipules
eventually caducous, narrowly triangular-ovate, 12-15 mm
long, 5-8 mm wide, reddish hyaline, herbaceous, weakly
or not keeled, glabrous, margin eciliate, apex aristate,