Abstract: The development or adaptation radiation of angiosperms has been closely related to the paleoclimate and paleoenvironment. Several environmental factors, influencing each other, have affected the evolution or development of angiosperms, which falls into different stages. The lines between these stages are not consistent with the traditional geological ages. Floristic regionalization might be better based on the stages of the development. Angiosperms have become important or dominant elements in the flora since the middle and late period of the Late Cretaceous. The development of angiosperms may be divided into four stages: (1) Initial stage: The angiosperms were not yet well established during the Early Cretaceous. The number of species and individuals was limited, the leaf small, mostly with entire margine, irregular venation and poor differentiation of venation; (2) Flourished stage: The angiosperms increased dramatically and became abundant. The leaf was larger with more regular venation and the differentiation of venation was remarkable. The percentage of angiosperms was from 40%-60% in the flora, and eventually arose, becoming predominant, with important families well presented. This was probably from the Late Cretaceous to the Early Tertiary; (3) Herbs-Flourished stage: Some of woody plants were extinct, while herbs greatly increased, because of the changes in climate, sea level and mountain uplift during the Neogene period; (4)Quaternary stage: The mountain glacier in China, influenced by global glacial-interglacial alternation due to the climatic fluctuation, advanced and regressed during the Quaternary. The climatic fluctuation apparently affected the distribution of plants. But the components of the flora were similar to or slightly different from the features of the present one. The aim of the present paper is to discuss the floristic regions at the second and third stages. The Late Cretaceous-Early Tertiary stage: A. The Late Cretaceous-Paleogene flora of northern China 1. Warm-temperate to subtropical deciduous broad-leaved and conifer forests in North and Northeastern China 2. Dry subtropical flora of Northwestern and Central China B. Southern China Late Cretaceous-Paleogene flora 3. Deciduous and evergreen forests with coniferous elements in the subtropical coastal region of east China 4. Evergreen forests of South China 5. Evergreen forests of lower mountains in the Tethys The Neogene stage-Herbs-flourished stage: 1. Temperate forests and grasslands to semidesert-desert floras of northwestern China; 2. Warm temperate deciduous forests of north and northeastern China; 3. Warm temperate to subtropical deciduous and evergreen forests of central and east China; 4. Evergreen forests of the subtropical and tropics mangrove vegetation of south China; 5. Subtropical evergreen and deciduous forests on the Yunnan and Xizang plateau.

Key words: Tertiary, Cretaceous, Vegetation, Angiosperms, Floristics, Evolution