首页分享地质时期樟科植物花化石及其系统演化意义

地质时期樟科植物花化石及其系统演化意义

来源：花匠小妙招时间：2024-11-10 20:25

摘要

This article systematically reviews the fossil record of the Lauraceae flower, including Androglandula, Lauranthus,Mauldinia,Neusenia,Perseanthus and Potomacanthus which were found in the geological times,the mor?phological characters,distribution,stratum and phylogenetic significance of these genera and species are systematically discussed. This article explores the stratum, distribution, inflorescence types, floral morphological characters, micro?structural characters with the modern Lauraceae. The results were as follows:(1)Lauraceae originated in the mid?lati?tude region of the Laurasia from middle to late Cretaceous.(2)Two inflorescences are found in the fossil flower of Lauraceae,one is Mauldinia type,which has elongated axes bearing distinctive,spirally arranged lateral,bilobed clad?ode?like units with five sessile bisexual flowers on the adaxial surface, the other is pseudoumbel type which has three sessile and closely spaced flowers with enclosed by two broad and strongly truncate bracets.(3)Bisexual flowers with three cardinal numbers,six perianth lobs arranging in two whorls,twelve or six stamens in four,three or two whorls,in?nermost whorl reduced to staminodes,the third whorl stamen usually bearing two sessile and distinct basal glandular pro?tuberances,anthers have two or four valved chamber,the gynoecium has single carpel.(4)A large number of oil cells, paracytic stomatal apparatus and unicellular hairs are often present on perianth. The flower fossils of Lauraceae provide geological and historical evidences for the phylogenetic evolutionary study of the Lauraceae.%该研究对地质时期樟科植物花化石的主要类群,即Androglandula、Lauranthus、Mauldinia、Neusenia、Perseanthus和Potomacanthus属分别从属和种的形态特征、分布、地层以及系统意义进行了论述,并结合现代樟科植物从地层和分布、花序类型、花部形态特征和显微构造特征进行了分析.结果表明:(1)樟科植物在中晚白垩纪期,已经起源于劳亚古陆的中纬度区域.(2)樟科植物的花序类型为Mauldinia属的侧生花序类型和假伞形花序类型.(3)花为3基数的两性花,花被片6枚排列为2轮,雄蕊12或6,排列为4、3或2轮,最内轮雄蕊不育,第三轮雄蕊基部常见一对附属腺体,雄蕊药室瓣裂,4或2药室,雌蕊为单心皮.(4)花被片上常有大量的油细胞、并列型气孔器和单细胞毛.该研究结果中樟科花化石的发现,为樟科植物的系统演化提供了古生物学的证据和资料.展开▼