云南上新世杜鹃属和松属化石木研究及其古气候意义

PLIOCENE RHODODENDRON AND PINUS FOSSIL WOODS OF YUNNAN PROVINCE AND PALAEOCLIMATE

研究了云南西部龙陵县上新世的化石木 ,鉴定出两种木材类型。杜鹃花科杜鹃属的似腋花杜鹃Rhododendroncf racemosumFranchet,其主要木材特征有散孔材 ,生长轮略明显 ,导管具多角形轮廓 ,螺纹加厚出现在整个导管壁上 ,梯状穿孔板 ,射线异形II型。松科华山松PinusarmandiiFranchet的主要特征有交叉场纹孔窗格状 ,具正常轴向和纵向树脂道 ,且泌脂细胞壁薄 ,射线管胞内壁平滑或具稀疏的微锯齿。两种类型的化石木在我国均属首次报道。根据化石木结构和现代相应树种和植被的生境范围 ,当时植物生长于亚热带温凉湿润的山地环境 ,其海拔大约在 1 80

Fossil woods collected from Pliocene sediments in the western Yunnan province are studied. Two types of wood are identified. One is Rhododendron cf. racemosum Franchet belonging to Ericaceae. Its key characters include wood diffuse porous, growth rings indistinct, vessel outline angular, perforation plates of vessel scalariform, helical thickenings throughout body of vessel element and ray heterogeneous type II. The other is Pinus armandii Franchet belonging to Pinaceae. Its key characters include cross fields pitting window like, normal axial and horizontal resin canals with thin epithelial cells present. Both fossil woods are firstly reported in China. Based on anatomical features and ecological condition of extant taxa and vegetation distribution, growth environment of fossil woods is subtropical humid upland climate at an altitude of 1 800 m or so.