Understanding Population Dynamics of Euptelea pleiospermum from Spatial Distribution Characteristics Potential Impacts of Climate Warming on Distribution of Euptelea pleiospermum along Altitude:An Experimental Simulation Chemical Constituents from Twigs of Euptelea pleiospermum Chromosome Number and Development of Gametophytes in Euptelea pleiospermum (Eupteleaceae) Pit-Membrane Remnants in the Perforation Plate of Euptelea pleiospermum (Eupteleaceae) Vessels Euptelea pleiospermum Community Characteristic of Dafang Karst Area in Guizhou,Southwest China QUANTITATIVE CHARACTERISTICS AND SPATIAL DISTRIBUTION PATTERNS OF EUPTELEA PLEIOSPERMUM POPULATIONS IN RIPARIAN ZONES OF THE SHENNONGJIA AREA, CENTRAL CHINA