山茶科紫茎属和舟柄茶属的系统学研究

本文对山茶科紫茎属和舟柄茶属进行了深入细致的系统学研究，藉助形态学、古植物学、孢粉学，细胞学和解剖学资料澄清了两属的分合问题，证实两属在各方面具有较大相似性，并且各分类特征存在广泛的联系而无法分开，从而赞同H．K．Airy Shaw，J．R．Sealy及S．A.Spongberg的主张，即将这两属合并。在此基础上本文提出了世界范围广义紫茎属下分类系统。属下新系统根据花柱合生程度、花序类型，苞片与萼片的形状以及两者的相对长度等特征，分为两个亚属，五个组，同时对该属种类进行修订。该属共有23种5变种，本文发表新组1个，新名称2个，新组合9个，新异名10个，新种1个，并附有分种检索表。广义的紫茎属为东亚-北美间断分布类型，中国南部和西南部是该属的起源中心和高度分化中心。根据化石资料推断，该属起源于早白垩纪，在第三纪以前于整个劳亚古陆上呈广泛而连续的分布，后因冰川及造山运动的影响，从而形成现在的分布格局。

A SYSTEMATIC STUDY ON THE GENERA STEWARTIA AND HARTIA (THEACEAE)

According to their morphology, palaeobotany, palynology, cytology and anatomy, the genera Stewartia and Hartia are reasonably combined together. This idea is identical with that of Airy-Shaw(1936), Sealy(1958) and Spongbeng(1974). A system of Stewartia s. 1. on world scale has been nwely suggested in this paper. Based on the connate degree of styli, inflorescence type, shape of bracteoles and sepals and their relative length, the genus is divided into two subgenera, five sections. The new system is as follows; Stewartia Linn. , s. 1. Subg. I. Dialystyla (Szysz. ) J. Li et Ming: St. ovata (Cavanilles) Weatherby, St. yunnanensis H. T. Chang. Subg. n . Stewartia Sect. 1. Racemosae(Wu)J. LietMing:5i. manadelpha Siebold et Zuccarini, St. sinii (Wu) Sealy, St. densiviUosa(Hu ex H. T. Chang et C. X. Ye) J. Li et Ming, St. obavata (Chun ex H. T. Chang)]. Li et Ming, Si. tonkinensis (Merr. )C. Y. Wu, St. crassifolia(S,. Z. Yan) J. Li et Ming, St. laotica(Gagnep. ) J. Li et Ming. Sect. 2. Stewartia :St. molocodendron Linn. Sect. 3. Serratae Nakai;S? rostrota Spongberg, St. serrata Maxim. St. sinensis Rehd. et Wils. Sect. 4. Pseudocamellia Nakai;5i. rubiginosa H. T. Chang, St. damingshanica J. Li et Ming, St. pseudocamellia Maxim. St. sichuanensis (S. Z. Yan)J. Li et Ming, St. micrantha (Chun) Sealy, St. calcicola Ming et J. Li. Sect . 5. Pteropetiolatae J. Li et Ming-.St. cordifolia (Li) J. Li et Ming, St. villosa Merr. St. medogensis J, Li et Ming, St. pteropetiolata W. C. Cheng. One new section and one new species are described; two new names, nine new combinations and ten new synonyms are reported. A key to the species is provided to aid in identification. Stewartia s. 1. is of the distribution pattern of E. Asia-N. America, originated and is strongly differentiated in S. and SW. China. According to the fossil data, it is suggested that Stewartia s. 1. originated in the early Cretaceous, and was widely and continuously distributed in Laurasia before the Tertiary. Influenced by the glaciers and orogenesis, the present distribution pattern of the genus is formed.