85 This chapter presents phylogenetic study of Malesian Diplazium by using
morphological datasets generated from sixty nine species from West Malesia. All data on the characters analyzed here are cited from this present work Chapter 9.
This study was conduct to address question of phylogenetic relationships among species within Diplazium. The objectives of this study were to: 1 to reconstruct
the phylogenetic relationships among the species in the genus Diplazium; 2 identify monophyletic species groups within Diplazium, 3 establish sister-group
relationships among these monophyletic groups.
6.2. Character Selection and Construction 6.2.1. Character Selection
Cladistic analysis is the most common method currently used to reconstruct phylogenetic trees, even it is the best method See Bremer
Wanntorp 1978, Estabrook 1978, Wiley 1980. For generating a set of trees, it involves two basis phase-exploration of characters including selection and
examination, followed by analysis of the data Thiele 1993. Thiele 1993 described an ideal morphological character as one in which the character states
vary between terminal units in the analysis but not in other members of the unit e.g. conspecific individuals being represented.
6.2.2. Character Type
In the morphological systematic studies, there are two types of characters used: qualitative and quantitative. Qualitative characters are mostly obtained by
examination without measurement. These characters can be divided into binary characters and multistate characters. Binary characters comprises two character
states, such as scales margin without thickening black strands or with thickening black strands, in character 14, Table 6.1.. Multistate characters consist of more
than two character states such as lamina division that comprise 7 character states simple, pinnatifid, imparipinnate, bipinnatifid, bipinnate, tripinnatified, and
tripinnate, in character 23, Table 6.1.. Generally, qualitative characters are more
86 acceptable and seem to be unambiguous in cladistic analysis because their states
are considered to be clearly defined and no overlapping Kitching et al 1998. Quantitative characters are obtained by measurement. Generally
quantitative characters are continuously variable. Continuously variable should only be exclude if the cladistic analysis cannot handle such data or if it can be
shown empirically that those characters convey no information of phylogenetic signal relative to other characters in the data matrix Kitching et al. 1998. In this
study quantitative characters are included in the analysis because they convey information of phylogenetic signal relative to other characters in data matrix.
Another argument for inclusion of quantitative characters is that some qualitative characters may be a collection or transformation of quantitative characters. For
example. Leaf shape a qualitative characters can be defined by ration of leaf length to leaf width, which is quantitative caharcters Thiele 1993.. Characters
number 7, 8, 16, 17, 25, 26, 37, 38, 49, 50, and 56 in the Table 6.1. are quantitative characters that are important and having tight correlation with the
qualitative characters examined. Excluding these characters would give illogical relationships among the species. Therefore these characters were included in
analyis.
6.2.3. Character Coding
