Dissertation Research: Systematics and Phylogeny of Dracontium (Araceae)

9310171 Croat和Zhu研究生Zhu在Croat博士的指导下，正在进行德拉贡属热带类昆虫的分类学研究，其中在新世界热带地区估计有20种。研究材料包括从各个国家和国际博物馆借来的保存完好的植物标本，并辅以将在东道国同事的帮助下在哥斯达黎加、委内瑞拉和厄瓜多尔采集的新的实地标本。研究人员正在分析其形态学和解剖学的新特征，包括花粉和染色体，以获得可靠的分类鉴别特征和建立稳定的物种分类。对传粉的实地观察将有助于了解不同物种间花形态的差异。许多热带植物群所知甚少，通常是几十年前各种自然历史考察所收集的单一或少量标本。本博士论文项目将重点研究与黄花属和红掌属有关的一组块茎蕨的新世界物种，将大大增加形态学和生物化学研究的可用标本，改进物种识别方法，更稳定的分类，并首次分析这些物种之间的系统发育关系以及推定的相关属。

9310171 Croat and Zhu Graduate student Zhu under the supervision of Dr. Croat is undertaking a taxonomic study of tropical aroids of the genus Dracontium, of which there are an estimated 20 species in the New World tropics. Materials for study include preserved herbarium specimens borrowed from various national and international museums and supplemented with new field collections to be made in Costa Rica, Venezuela, and Ecuador with the help of host country colleagues. New features of morphology and anatomy including pollen and chromosomes are being analyzed, to acquire reliable characters for taxonomic discrimination and for construction of a stable classification of the species. Field observations on pollination will help understand the differences in floral form among the species. %%% Numerous groups of tropical plants are poorly known, often from single or few collections made decades ago by various natural history expeditions. This doctoral thesis project will focus on the New World species of a group of tuberous aroids related to philodendrons and anthuriums, and will result in greatly increased collections available for morphological and biochemical studies, as well as improved methods of species recognition, a more stable classification, and the first analysis of phylogenetic relationships among these species and with putatively related genera.