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8.4. Conclusions
Gene rbcL sequence is very well in supporting species delimitation among species within the genus Diplazium. Even this study also showed most of West
Malesian species are showing genetic diversity, mainly those having polyploidy types or seri ploidy. Therefore the division of D. pallidum into two varieties is
supported with this gene rbcL sequences. This study give an indication that species in which have both morphological difference and seri ploidy, such D.
accedens, D. cordifolium, D. crenatoserratum, D. bantamens, D. subserratum and
D. tomentosum , should be more studied by encompassing much more sample from
their range of distribution. This study revealed that gene rbcL is more informative in inferring
phylogeny of the genus Diplazium in West Malesia. Therefore the phylogenetic analysis of gene rbcL sequences found that Diplazium in West Malesia is
monophyletic. The position of D. porphyrorachis at the basal clade of the philogenetic
tree generated from morphological data and separated from other species is supported by the phylogenetic tree generated from molecular data gene rbcL
sequence. This result is in accordance with the statement of Price 1983 that D. porphyrorachis
and close related species are belonging to the different lines within the genus Diplazium. This study also showed the congruence between the
clade of ‘riparium Group’ drawn by rbcL tree and morphological tree. The result of this study also showed that the classification of van
Alderwerelt van Rosenburgh 1908 is not monophyletic. The classification of Kato 1977 in dividing Japanese Diplazium into six group can not be referred to
West Malesian Diplazium. Moreover the Diplazium groups of Kato 1977 are also not monophyletic.
This study indicates that some uncertain relationships require further analysis in the future. More data, including both more taxa that include all West
Malesian species and from wider areas and more molecular data, are needed before a well resolved phylogenetic hypothesis for West Malesian Diplazium can
be offered.
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CHAPTER 9 TAXONOMIC STUDY OF THE FERN GENUS DIPLAZIUM
IN WEST MALESIA 9.1. Introduction
The genus Diplazium was established by Swartz 1801 and typified by Asplenium plantaginifolium
L Diplazium plantaginifolium Sw.. Since then, a total of 1401 of binomials have been published by various authors for Diplazium
in the world IPNI, 2006. Hassler Swale 2002 listed 474 species and 8 hybrids of Diplazium in the world.
Malesian region is the center of Diplazium diversity as it was predicted that 75 of species in world ca.300 species are existing in this region Roos,
1995. However, since van Alderwereld van Rosenburgh 1908, there has not been a comprehenship study, including a revision, on Malesian Diplazium, yet.
Previous workers only studied Diplazium based local area. Holttum 1940, 1966 in his revision on ferns of Malaya reported 27 species of Malay Peninsula.
Tagawa 1972 listed 15 species of Diplazium from Borneo. Iwatsuki Kato 1984 reported 15 species of diplazioid ferns of East Kalimantan. Parris et al
1992 listed 31 species from Mt. Kinabalu. Mitsuta 1985 listed 11 species from West Sumatra. In Java, Backer and Posthumus 1939 decribed 17 species. Sixty
years after that Praptosuwiryo 1999 recognized 22 species and 4 varieties of Java. Kato 1994 reported 32 species of Diplazium from Ambon and Seram
Moluccas. This chapter presented the account of West Malesian Diplazium. The aims
of this study are: 1 to revise the genus Diplazium in West Malesia; 2 to provide the delimitation of the genus and species, and 3 to provide an
identification keys to the species and infra species.
9.2. Materials and Methods
Morphological study on Diplazium covered West Malesian species have been conducted. This study is based mainly on available specimens housed at the
BO and SING and new collection specimens obtained from field work study in
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