DISSERTATION RESEARCH: Systematics, Evolution, and Biogeography of Lepechinia (Lamiaceae)

唇形科（Lamiaceae）唇形科（Lepechinia）植物的系统学、进化和植物地理学研究唇形科（Lamiaceae）唇形科（Lepechinia）植物是一组开花植物，以提供用于烹饪的草药和用于园艺的香料而闻名。 在加州，一组薄荷属的种类出现在被称为加州植物区系省的地区，该地区从南俄勒冈州延伸到北方巴哈。 该项目将使用Lepechinia和化石的DNA序列来确定加州植物区系省的起源时间。 额外的DNA序列将被用来确定如何密切相关的Lepechinia是其他组的薄荷。最后，DNA数据将用于评估在进化过程中，Lepechinia的形态和繁殖系统是如何变化的。 加州植物区系省有许多世界上其他地方没有的植物物种。 由于其高度的多样性和独特的物种组合，人们对了解它存在了多久以及它是如何形成的有相当大的兴趣。 Lepechinia和它的近亲鼠尾草（一种常见的园林植物）可以帮助确定植物群的年龄。 这项研究的初步结果表明，加州的枝叶山龙眼属和鼠尾草属起源于1000万至2000万年前，可能来自生活在更远的南方的祖先。

Systematics, evolution, and biogeography of Lepechinia (Lamiaceae)AbstractThe mint family (Lamiaceae) is a group of flowering plants that is well known for providing herbs used in cooking and ornamentals used in gardening. Many wild species also colour the landscape of the U.S. In California, a group of mint species in the genus Lepechinia occur in the area known as the California Floristic Province, a region extending from Southern Oregon to Northern Baja. This project will use DNA sequences of Lepechinia and fossils to determine when the California Floristic Province originated. Additional DNA sequences will be used to determine how closely related Lepechinia is to other groups of mints. Finally, the DNA data will be used to assess how the morphology and breeding system of Lepechinia have changed during evolution. The California Floristic Province has many plant species that occur nowhere else in the world. Because of its high diversity and unique set of species, there has been considerable interest in understanding how long it has been in existence and how it formed. Lepechinia and its close relative Salvia (a familiar garden plant) can help to determine the age of the flora. Preliminary results of this study show that the California clades of Lepechinia and Salvia originated between 10 and 20 million years ago, probably from ancestors that lived farther to the south.