The Evolution and Sources of the Flora in Shandong Province

A ccording to the comparative analysis of the material between paleobotany and modern flora,the evolution and sources of Shandong's flora are preliminarily studied.The nature of Shandong's modern flora is temperate with subtropical tropical transitional character.The evolution process of the flora is as follows:pteridophyta was prosperous in Paleozoic;gymnosperm was dominated in Mesozoic;angiosperm appeared and developed rapidly and there lived the tropical-subtropical evergreen broad leaved forests in Cretaceous;in Paleogene and Neogene of Cenozoic,there lived subtropical evergreen and deciduous broad leaved mixed forests,and temperate-subtropical deciduous and evergreen broad leaved mixed forests respectively.In Quaternary Period,the flora was dominated by deciduous forests,but along with the alternation of glacial and interglacial epoch during the Pceistocene,the frigid temperate conifer and the subtropical evergreen elements replaced each other,and since Holocene the distribution pattern of modern warm temperate deciduous broad-leaved forests and temperate coniferous forests has been formed;the flora mainly originated and evolved from the local flora in Paleogene Period,partly from Norteastern Asia,the Himalayas and Transversal Mountains of southwestern China,a little from Middle Asia and Chinese northwestern dry area.