Botanical Studies (2006) 47: 443-452.
Corresponding author: E-mail: firstname.lastname@example.org; Tel: 0487-
2699-061; Fax: 0487-2699-249.
Rattans are spiny climbing palms belonging to the
subfamily Calamoideae of the Arecaceae (Uhl and
Dransfield, 1987). They comprise about 600 species in
13 genera distributed in equatorial Africa, South Asia,
Southern China, the Malay Archipelago, Australia and the
Western Pacific. Rattans form one of the major non-wood
forest products in international trading. Approximately
700 million people trade or use rattan for different
purposes worldwide mainly for furniture and cottage
industries. The global trade and subsistence value of rattan
and its products is estimated at over US$ 7,000 million
per annum (Pabuayan, 2000). Due to overexploitation,
habitat degradation and low regeneration capacity, the
rattan resources of the world are under serious threat. It is
estimated that around 117 species of rattans are treated as
threatened to some degree (Walter and Gillet, 1998).
In India, rattans comprise about 60 species in four
genera¡Xviz. Calamus, Daemonorops, Korthalsia, an d
Plectocomia¡Xdistributed in the Western Ghats, North
Eastern states, and the Andaman and Nicobar Islands.
Calamus rivalis and C. metzianus are two slender
diameter rattans found in the Western Ghats and Sri
Lanka. Calamus metzianus was first described by Schlecht
(cf. Beccari, 1908) based on specimens collected by Rev.
Metz from the Canara district of Karnataka, India. It was
later discovered in Nilambur of Kerala, India (Renuka
and Bhat, 1987). Calamus rivalis was originally described
from Sri Lanka by Thwaites and was validly published by
Trimen (Beccari, 1908). This species was also distributed
in Ashramam (Kollam) and Chertala (Alapuzha) of India.
Beccari (1908) suggested that C. metzianus represented
the continental form of C. rivalis and this species could be
distinguished from C. metzianus by a larger fruit size and
distinctly channeled fruit scales.
The purposes of the present study are to examine
the patterns of phenetic structure and levels of genetic
variation within and among populations of these two
species using random amplified polymorphic DNA
(RAPD) markers and morphological characters. The
RAPD protocol is relatively quick, easy to perform, and
requires no sequence information prior to analysis and
only a nanogram quantities of DNA (Williams et al.,
Taxonomic reconsideration of Calamus rivalis Thw. ex
Trim. and C. metzianus Schlecht (Arecaceae) through
morphometric and molecular analyses
, C. RENUKA
*, T.B. SUMA
, and M. BALASUNDARAN
Division of Forest Ecology and Biodiversity Conservation, Kerala Forest Research Institute, Peechi, Thrissur, 680 653,
Division of Sustainable Natural and Plantation Forest Management, Kerala Forest Research Institute, Peechi, Thrissur,
680 653, Kerala, India
(Received November 19, 2004; Accepted March 31, 2006)
Molecular and morphometric analyses of different Indian and Sri Lankan populations of two
rattan species (Calamus rivalis and C. metzianus) were carried out using Random Amplified Polymorphic
DNA (RAPD) markers and morphological characters. Multivariate analysis of RAPD and morphological data
failed to separate these populations into two distinct species. RAPDs generated a total of 117 markers with
10 decamer primers, of which 95 percent were polymorphic. The percentage of polymorphic loci between
populations varied from 26.5 to 68.38, and genetic distance between populations ranged from 0.05 to 0.28.
The genetic variation within populations was greater than the variation among populations. Both the RAPD
and morphometric data suggest the existence of a single species, and hence C. rivalis can be merged to C.
Keywords: Calamus; Dendrogram; Genetic diversity; RAPD.