（様式７）

Title of dissertation Taxonomic, molecular phylogenetic and ecological studies on Podostemaceae in the Phetchabun Mountain Range, RONPAKU Fellow Name Petcharat WERUKAMKUL Position Lecturer ID No. R11514 Department Faculty of Science and Technology Institution Rajamangala University of Technology Phra Nationality Thailand Nakhon Japanese Advisor Name Moritoshi IINO Position Professor Institution Osaka City University

The Podostemaceae are the largest family of aquatic angiosperms, living in rapids and waterfalls. Although previous floristic studies of Podostemaceae in the Phetchabun Mountain Range recorded 4 genera and 9 species, the exploration did not cover its whole area. This study conducted field exploration especially focusing on the Phetchabun Mountain Range with the largely mountainous terrains in its northern zone, i.e., Chaiyaphum, , Phetchabun and provinces which contain sedimentary rocks with many rapids and waterfalls, and performed taxonomic studies based on comparative morphology and molecular phylogenetic analysis using matK sequences. The results indicated that the Podostemaceae are classified into 2 genera and 6 species of subfamily Tristichoideae, and into 5 genera and 18 species of subfamily Podostemoideae. The results of this study found 7 new species and one variety: Dalzellia sparsa, Terniopsis filiformis, T. heterostaminata, Hydrobryum chompuense, H. mandaengense, H. phurueanum, H. varium and H. phetchabunense var. major and 2 new records to Thailand: H. vientianense and Polypleurum pluricostatum, and 6 new records to the Phetchabun Mountain Range: T. chanthaburiensis, T. minor, P. longicaule, P. prachinburiense, P. wallichii and Thawatchaia trilobata. Dalzellia sparsa is distinguished from the congeners by the leaves on the cupule. Terniopsis filiformis is characterized by the three or rarely two stamens, stigma cristate when young, forked and filiform at maturity. Terniopsis heterostaminata is characterized by the two or rarely three stamens, the third stamen appearing later than the others and somewhat abortive. Hydrobryum chompuense, which is recognized by the bracts ovate with acute, acuminate or caudate apex, is sister to H. varium. Hydrobryum mandaengense is unique in the disporangiate anthers with tortuously lengthwise and introrsely dehiscence, and phylogenetically it is close to H. tardhuangense. Hydrobryum phurueanum is recognized by the semicircular sheathing base of bracts with long caudate apex, and it is sister to Hydrobryum kaengsophense. Hydrobryum varium, which is distinguished from other congeners by the oval spathella, long capsule stalk, variable length of andropodium and filament, is sister to H. chompuense. Hydrobryum phetchabunense var. major differs from var. phetchabunense in the size of organs, number of ovules and number of capsule ribs. Hydrobryum is the largest genus in the Phetchabun Mountain Range with 11 species out of 16 species in Thailand. All 24 species were found on the rocks that are constituted with sedimentary rocks. In the field observations, Dalzellia kailarsenii of Tristichoideae occurs on lower part of rocks while P. wallichii of Podostemoideae occurs on nearly whole part of rocks. It may be implied that the adaptation of Podostemaceae occurred with the invasion into deep areas in rivers and the deviation of Podostemaceae occurred with expansion of habitat. Among the endemic species, 10 species are restricted to one to four river systems in the Phetchabun Mountain Range. Loei province is the center of species-rich area with 12 species, followed by with 11 species, with 6 species and with 4 species. The results indicate that Podostemaceae in the Phetchabun Mountain Range account for 46.2% of Thai’s species, and this area is a center of diversity for Podostemaceae in Thailand.

Photos

2016 年 1 月 21 日 Kaeng Sopha Waterfall, Tung 2016 年 12 月 7 日 Phu Khiew wildlife sanctuary Salaeng Luang Natl. Park（タイ）での調査 （タイ）での調査