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
The crucial point in the phylogenetic analysis using morphological datasets is how features might be usefully coded so as to reflect accurately our
observations for particular scale problem Kiching et al 1998. Character coding is the link between observation and explanation Strong Lipscomb 1999.
Therefore, ability, or inability, of a coding method to reflect the evidential significant of observations should be the primary concern in considering
alternative methods of coding. Basing on the philosophy above, in cladistic analysis of morphological
characters in Diplazium, a conservative approach of ‘composite characters coding’ Strong Lipscomb 1999 was employed. Composite coding refers to the
creation of single multistate character from several potentially dependent character method ‘A’ in Kitching et al 1998 that designed to minimize the effect
87 of character linkage. Kitching et al 1998 stated that the more that characters
become linked, i.e. dependent on other characters, the greater is the departure from independence and consequently the risk that one false homology can obscure
the topologies of true homologies decreased. Composite coding applied in this study was also designed to reduce the
error that extensive amounts of missing data a character state scored as ‘?’ can create in a parsimony analysis Maddison 1993. The fronds architecture of
Diplazium are varying, from simple to quadripinnate. Consequently taxa with
simple, pinnate, bipinnate fronds do not posses any organ that possessed by those with pinnate, bipinnate and tripinnate fronds, respectively.
Character 36. Table 6.1 is an example of composite characters in this study. It was created from the combination of two characters: 1 Lateral pinnae
existnot exist and 2 Shape of lateral pinnae oblong oblong lanceolate elliptical liniery triangular oblong subtringular lanceolate ovate. These two
characters in which the latter is dependent on the former, were combined into a single character with eight character states lateral pinna oblong oblong
lanceolate elliptical liniery triangular oblong subtringular lanceolate ovate organ not exist. This method reduced the numbers of linked characters and
limited the influence of multiple missing characters states on the analysis for previously coded characters ‘lateral pinnae oblong oblong lanceolate elliptical
liniery triangular oblong subtringular lanceolate ovate’ in those taxa which have no lateral pinnae. Maddison 1993 stated that missing character states can
cause difficulties for parsimony analysis if the missing state for the character occurs in more than one clade.
6.3. Character Variation within West Malesian Diplazium
