This paper deals with the classification, evolution and distribution of Sect. Thea.The results of these studies may be summarized as follows:
1) In the last years, a great number of new species in Sect.Thea and Sect.Glaberrima are reported. Accoding to the investigation and comparative studies on two Sections and about 47 species, Sect.Glaberrima is merged into Sect.Thea, 12 species and 5 varieties are determined in Sect.Thea.
2) By the numbers of ovaries-locular, the size of sepals and petals, the characters of leaves and pedicells etc.., the diversity and evolutionary tendencies of species are discussed. It can be regarded that species with 5-locular ovaries, large sepals and petals are more primitive than 3-locular ovaties, small sepals and petals.
3) Sect. Thea are distributed in East Asia, including south of Yangtze river in China, the south of Japan and the north of Indo-China peninsula.The center of distribution lies in the south-western and southern parts of China, all species are concentrated here. In accordance with the analysis of the differentiation and distribution of species, the Sect.Thea can be evolved from Sect.Archecamellia and originated in subtropical calcareous mountains of Yunnan and Guizhou as well as Guangxi.
4) The paper makes a exposition of rich resources and utilizable potentialities of theSect.Thea in China. It is important to protect effectively and utilize retionally tea resources.
Acta Botanica Yunnanica