中国木兰亚科植物的主要分类性状观察

An Observation on the Main Taxonomic Characters of Subfamiliy Magnolioideae in China

对木兰亚科植物花的着生式样、心皮中的胚珠数目和花的性别等主要分类性状进行了研究。在毛果含笑、云南含笑等含笑属植物中观察到了顶生花。含笑属的聚伞花序不是一个花序 ,而是一个具有多花的枝条 ,其“总花梗”实质上是一个枝条 ,其节上的花顶生于次级侧枝上 ,属于顶生花式样。山玉兰和盖裂木每心皮中的胚珠数目为 2～ 7个 ,而不是 2个。在山玉兰、黄兰、合果木等植物上观察到了单性雄花 ,而在云南拟单性木兰的雄株上观察到了少数具有 1～ 8个心皮的两性花。根据观察结果 ,本文讨论了这 3个主要分类性状在木兰亚科分类系统中的意义 ,并对现有分类系统进行了分析 ,在此基础上对中国木兰亚科的分类系统做了修订 ,依据分枝式样、花药的开裂方式 ,将中国木兰亚科植物归并为木兰属和含笑属。

The main taxonomic characters, such as patterns of floral position,number of ovule per carpel and sexuality of flower in many species of subfamily Magnolioideae were observed in both field and cultivated states (Kunming Botanical Garden). The terminal flowers were observed in some plants of tribe Michelieae that was thought having only axillary flowers before,such as M.yunnanensis,M.sphaerantha,M.figo,M.macclurei,M.balansae .The axillary flowers of tribe Michelieae ,in fact,occur terminally on the abnormal short shoots, which arise from the leaf axils and grow abnormally. In contract, the terminal flowers occur on normal shoots. In the period of alabastrum, the flowers of Magnolia denudata and M.soulangiana of tribe Magnolieae occur terminally on short shoots although they seem like occurring axillaryly. All flowers of subfamily Magnolioideae actually occur terminally on shoots at morphogenesis on the basis of our observations.In genus Michelia ,the so-called cyme with 2-3 flowers is a branch with lateral branchlets according our observations.The so-called “peduncle” is a branch and the “pedicel” is the lateral branch at morphogenesis. The flowers occur terminally on abnormal branch and lateral branchlets. These observations suggest the close relationship between the tribe Magnolieae and tribe Michelieae .Meanwhile,2-7 ovules per carpel, which are the same to that of Manglietia ,were observed in Magnolia delavayi and Taluama hodgsonii that were thought having 2 ovules per carpel before. This observation shows the number of ovule per carpel is not a good character for delimitating Manglietia form Magnolia .A lot of staminate flowers were observed in some taxa that were thought having only bisexual flower before,e.g, Magnolia delavayi,Michelia champaca and Paramichelia baillonii .In addition,1-8 carpels were observed in the staminate flowers of Parakmeria yunnanensis ,an androdioecious species.According to our observations, the classification system based on the characters,such as patterns of floral position, number of ovule per carpel and polygamo-dioecism, cannot correctly reflect the phylogenic relationships among the taxonomical groups. Based on the branching patterns, the dehiscing patterns of anthers et al ,the classification system of Magnolioideae in China is revised here as follows:Magnolioideae1. Magnolia (Subgenus Magnolia Syn.nov, Alcimandra,Manglietia Syn.nov, Manglietiastrum, Talauma , Parakmeria,Kmeria Syn.nov, Woonyoungia Syn.nov.)(sylleptic branching; flowers appearing after leaves;anthers introrsely dehiscent)2. Michelia (Subgenus Yulania Syn.nov, Michelia,Paramichelia,Tsoongiodendron )(proleptic branching;flowers appearing before leaves;anthers laterally or sublaterally dehiscent)