作 者 ：Tao Jun-Rong
期 刊 ：植物分类学报 1992年 1期
Keywords:Tertiary, Cretaceous, Vegetation, Evolution,
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 en-
tire 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 pres-
ent 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.