1�� Research Center of Paleontology and Stratigraphy��Jilin University��Changchun 130026��China; 2�� Key Lab for Evolution of Past Life and Environment in Northeast Asia��Jilin University��Changchun 130026��China; 3�� School of Biology��Suranaree University of Technology��Mueang��Nakhon Ratchasima 30000��Thailand

The Miocene-Pleistocene petrified woods are very abundant and well preserved in the area of Suranaree subdistrict��Nakhon Ratchasima��northeastern Thailand�� Twenty three specimens of the petrified woods have been studied by the authors��and determined to comprise at least 17 species of 10 genera��including 13 eudicot angiosperm taxa assigned to 7 genera of 6 families�� The taxa are Canarium sp�� ( Burseraceae) ; Terminalia sp�� vel Combretum sp�� ��Terminalia sp�� ( Combretaceae) ; cf�� Irvingia sp�� ( Irvingiaceae) ; Cynometroxylon holdeni��Cynometroxylon sp�� ��cf�� Cynometroxylon spp�� ��cf�� Millettia spp�� ( Leguminosae) ; Careya spp�� ( Lecythidaceae) ; and Azadirachta sp�� ( Meliaceae) ��etc�� In addition��there are 4 taxa ( incertae sedis) needed further study�� The highly diverse paleoflora shows a close resemblance in the floristic characters to the modern flora of mixed deciduous�� dry dipterocarp��and dry evergreen forests in northeastern Thailand��which implies that the paleoclimate in the area was probably tropical wet and dry��corresponding to the present climate but with higher humidity��