Allozymic Genetic Diversity in Eurycorymbus caraleriei (Levl.)Rehd.et Hand.-Mazz., an Endemic and Dioecious Tree in China Characteristics of Riparian Rare Plant Communities on the Shennongjia Mountains,Central China Evolutionary donservatism of floristic characteristics of relict Alsophila spinulosa community Regenerative condition and analysis of spatial distribution pattern of two relic plants in Mao’ershan Mountain, China