Dissertation Research: Integrating Phylogenetic and Taxonomic Studies of the Commelinaceae using Molecular and Morphological Data

9902015 Davis和Hardy开花植物科Commelinaceae由大约41属650种多年生或偶尔一年生草本植物组成，分布于世界各地的温带和热带地区。也被称为“蜘蛛科”，包括常见的栽培观赏植物，如紫露草和玉米草(蜘蛛科和流浪犹太人)。常见的野花包括各种不同种类的牵牛花(牵牛花)以及其他属。数量更多但鲜为人知的是该科的热带属，其中一些正在由研究生克里斯托弗·哈迪在康奈尔大学杰罗尔德·戴维斯博士的指导下进行研究。该项目的目标是在该科内对原产于中美洲和南美洲热带森林的三个密切相关的属进行系统发育和分类学研究。这些属是Cochliostema，Gegenantus，以及一个未描述的属，估计由6到7个新种组成。Cochliostema的植物在盆花科中是不寻常的，因为它们主要作为附生植物生长在森林的树冠上，一些植物具有类似菠萝科植物的“水箱植物”习性。Cochliostema的植物也拥有该家族中已知的最大的花。主要由五种亚马逊植物组成；矮生根茎植物的主要特点是在土壤表面和叶下开花的不寻常习性。最后，未被描述的属的植物是莲座状的林下植物，通常具有下面深紫色的叶和上面明亮的白色纵向条纹。这项研究的系统发育部分的目的是更好地了解这三个属和十三到十四个种之间的相互关系和与该科其他成员的关系。除了分析核基因和叶绿体基因的DNA序列外，还将通过分析花和营养结构的变异来推断系统发育关系。这一系统发育中的进化分化序列将建立关于该群中大型和奇怪的花型进化的假说。这一组的分类处理(专著)将包括几个属的所有种的检索表和新的或更新的描述。

9902015Davis and Hardy The flowering plant family Commelinaceae consists of approximately 41 genera and 650 species of perennial or occasionally annual herbs distributed throughout temperate and tropical zones worldwide. Known also as the "Spiderwort Family", the Commelinaceae includes familiar cultivated ornamentals such as Tradescantia and Zebrina (the spiderwort and wandering jew). Common wildflowers include various species of Commelina (dayflowers) among other genera. More numerous but less well known are the tropical genera of the family, some of which are being studied by graduate student Christopher Hardy under the direction of Dr. Jerrold Davis at Cornell University. The goals of this project are to conduct phylogenetic and taxonomic studies within the family on three closely related genera native to the tropical forests of Central and South America. These genera are Cochliostema, Geogenanthus, and an undescribed genus consisting of an estimated six to seven new species.Plants of Cochliostema are unusual for the Commelinaceae in that they are found growing primarily high in forest canopies as epiphytes, some with the "tank plant" habit that resembles bromeliads vegetatively. Plants of Cochliostema also possess the largest flowers known in the family. Geogenanthus consists of five primarily Amazonian species; low growing and rhizomatous, plants of Geogenanthus are distinguished primarily by their unusual habit of bearing flowers at the soil surface and beneath the leaves. Finally, plants of the undescribed genus are rosette understory plants often possessing leaves with deep purple beneath and a brilliant white longitudinal stripe above. The objective of the phylogenetic component of this research is to better understand how these three genera and thirteen to fourteen species are related to one another and to other members of the family. Inferences of phylogenetic relationships will be obtained by analyzing variation in floral and vegetative structure in addition to DNA sequences from nuclear and chloroplast genes. The sequence of evolutionary divergences in this phylogeny will establish hypotheses about the evolution of the large and bizarre floral forms in the group. A taxonomic treatment (monograph) of this group will include keys and new or updated descriptions of all species of the several genera.