Judul: Biosystematic Study of the Fern Genus Diplazium in West Malesia, Biosystematic Study of the Fern Genus Diplazium in West Malesia
Abstrak: Diplazium is a large genus consisting of about 400 species occur mainly in the tropics, sparingly in the subtropic and only locally extending into temperate. It was estimated that 300 species of the records were occurred in Malesia. Taxonomically, Diplazium is very difficult and quite insufficiently known. Therefore a comprehensive study on Diplazium in West Malesia was conducted by using morphological, ecological, geographic distribution, anatomical, palinological, cytological, as well as DNA analysis to understand the diversity and relationship among species. Based on gross morphological study on 1051 collection number of specimens as well as living collections, it was concluded that West Malesian Diplazium comprises of 69 species with 14 varieties. Thirteen species of them are proposed and described as new species, namely Diplazium asymmetricum, D. batuayauense, D. crameri, D. densisquamatum, D. halimunense, D. loerzingii, D. megasegmentum, D. megasimplicifolium, D. meijeri, D. parallelivenium, D. profluens, D. subalternisegmentum, and D. subvirescens. Two new varieties are poposed, namely D. accedens var. spinosum and D. silvaticum var. pinnae-ellipticum. D. pallidum var. montanum and D. accedens var. ridleyi are proposed as new status. Based on their main habitats, Diplazium can be classified into three major groups, viz. dryland (dominant), riparian and rheophytic species. Species diversity was culminated at 1000- 1500 m above sea level. The individuals with different genetic load in the same species sometimes grow in the different habitat gradients. Based on the range of the geographical distribution, West Malesian species can be divided into three types: (1) very wide species (19 species), (2) Malesian species (27 species), and (3) locally endemic species (23 species). Anatomical study on the transversal section of stipe of 27 species showed that the vascular bundle shape is varying among species. Therefore the leaf-trace shapes are important diagnostic features which support species delimitation in Diplazium. Spore morphology study showed that perine ornamentations support in delimitating species in Diplazium. However the phylogenetic analysis using parsimony revealed that morphological variation of spore is inadequate to depict natural relationship among Diplazium species. Cytological study on 117 collection number from 54 localities included in 31 species found that West Malesian Diplazium has six ploidy levels with x = 41 (diploid, triploid, tetraploid, pentaploid, hexaploid, and octoploid). New cytological information for science on 19 species are recorded. They are D. aequibasale (2n = 164), D. angustipinna (2n = 123). D. asymmetricum (2n = 123), D. batuayauense (2n = 164, 205), D. crenatoserratum (2n = 123, 164), D. halimunense (2n = 123), D. hewittii (2n = 123), D. profluens (2n = 164), D. loerzingii (2n = 82, 123), D. pallidum (2n = 82), D. petiolare (2n = 82), D. porphyrorachis (2n = 164), D. riparium (2n = 82, 123), D. spiniferum (2n = 82), D. subserratum (2n = 82, 123, 164), D. subvirescens (2n = 123), D. tomentosum (2n = 82, 205), D. xiphophyllum (2n = 82, 246), and D. wahauense (2n=164). Phylogenetic analysis on morphological data sets of 69 species using parsimony revealed that the phylogenetic relationship among species in the genus Diplazium was very difficult to explain due to the lack of or weak support
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