Botanical Studies (2009) 50: 89-100.
*
Corresponding author: E-mail: crsheue@mail.ncyu.edu.tw;
Tel: +886-05-2717827; Fax: +886-05-2760164.
**Co-Corresponding author. E-mail: tsaicc9017@yahoo.
com.tw; Tel: +886-08-7746735; Fax: +886-08-7229466.
INTRODUCTION
Ceriops Arn. is one of the mangrove genera in the
family Rhizophoraceae, with a widespread geographical
range from eastern Africa throughout tropical Asia, and
northern Australia to Melanesia, and through Micronesia
north to southern China (Tomlinson, 1986). It typically
grows in the inner mangroves, often forming pure stands
on better drained sites or becoming stunted in exposed and
highly saline sites, within the reach of occasional tides
(Hou, 1958).
The last revision of the genus Ceriops was done by
Hou (1958), with two species recognized: C. tagal (Perr.)
C. B. Rob. and C. decandra (Griff.) Ding Hou. Some 20
additional names, including several infraspecific names
were synonymized for them, but a variety name C. tagal
(Perr.) C. B. Rob. var. australis C. T. White named by
White (1926) was not listed.
White (1926) noticed a form of C. tagal in which the
propagules had smooth, terete hypocotyls rather than
the angled or ribbed hypocotyls typical of C. tagal from
Australia and Papua New Guinea. He initially intended to
describe this form as a new species distinct from C. tagal,
based on the "less distinctly veined, and more inclined
to recurved" leaves (White, 1926). After examining
additional specimens, however, he found those differences
between the new form and C. tagal were not constant
Reevaluating the taxonomic status of Ceriops australis
(Rhizophoraceae) based on morphological and
molecular evidence
Chiou-Rong SHEUE
1,
*, Yuen-Po YANG
2
, Ho-Yi LIU
2
, Fu-Shan CHOU
3
, Hsiu-Chin CHANG
1
,
Peter
SAENGER
4
, Christopher P. MANGION
5
, Glenn WIGHTMAN
5
, Jean W. H. YONG
6
, and Chi-Chu
TSAI
7,
**
1
Department of Biological Resources, National Chiayi University, 300 Syuefu Rd., Chiayi 600, Taiwan
2
Department of Biological Sciences, National Sun Yat-sen University, 70 Lien-hai Rd., Kaohsiung 804, Taiwan
3
Liouguei Research Center, Taiwan Forestry Research Institute, 198 Chunghsing Village, Liouguei 844, Kaoshiung
County, Taiwan
4
School of Environmental Science and Management, Southern Cross University, Lismore NSW 2480, Australia
5
Department of Natural Resources, Environment and the Arts, PO Box 496, Palmerston NT 0831, Australia
6
Natural Sciences, National Institute of Education, 1 Nanyang Walk, Nanyang Technological University, 637616
Singapore
7
Kaohsiung District Agricultural Improvement Station, 2-6 Dehe Rd., Changihih Township, Pingtung County 908, Taiwan
(Received December 24, 2007; Accepted August 19, 2008)
ABSTRACT.
Ceriops australis (White) Ballment, Smith & Stoddart, a member of the mangrove family
Rhizophoraceae, was originally recognized as C. tagal var. australis White but was raised to species rank
based solely on isozyme features and the only distinctive morphological feature of the hypocotyl. Therefore,
it was considered a sibling species of C. tagal (Perr.) C. B. Rob. The goal of this study was to test the
previous assessment that C. australis and C. tagal differ consistently only in hypocotyl morphology, in order
to reevaluate the taxonomic status and to establish its geographic range. Principal components analysis was
employed to analyze 29 morphological characters of herbarium specimens from Australia, Madagascar, and
Sumatra tentatively identified as C. australis and C. tagal, and two well differentiated distinct taxa were
recognized. In addition, both of the detailed morphological features based on fresh and herbarium materials
and the intron sequences of trnL gene from plastid DNA support this conclusion. This finding disagrees
with previous assessment and supports the current taxonomic status of C. australis. Here, a key to these two
species is provided, and a revised distribution range of C. australis is established. This is the initial report of C.
australis¡¦ occurrence in a part of Indonesia, in addition to areas of Australia and Papua New Guinea.
Keywords: Australia; Ceriops tagal; Ceriops; Distribution; Indonesia; Mangroves; Papua New Guinea; Plastid
DNA; Principal components analysis.
TAxONOmy