Chemosystematics and Phylogenetics of South American Xanthoparmeliae

地衣是一种共生生物， 真菌 它们占据了大约8%的陆地 生态系统，是矿物循环的重要贡献者， 许多领域。 它们也是重要的生物指标， 二氧化硫等污染危害。 托马斯纳什博士 亚利桑那州立大学正在研究 南美的黄梅属，以确定 可靠的形态和生化特征， 识别个别物种，并进一步尝试确定 这些分类群的进化亲缘关系。 百篇小说 化学化合物（所谓的“地衣物质”）已经被 在各种地衣中被发现，有时被用作物种 标记。 纳什博士将测试这些化学物质是否 特定物种的稳定特征，或者 在不同的环境条件下， 成长 他对南美地衣的分类工作将 补充正在进行或已完成的项目， 非洲、澳大拉西亚和北美，最终覆盖了 近400种。

Lichens are symbiotic organisms composed of both an alga and a fungus. They dominate approximately 8% of terrestrial ecosystems and are important contributors to mineral cycling in many areas. Also they are important biological indicators of pollution hazards such as sulfur dioxide. Dr. Thomas Nash of Arizona State University is studying the species of lichens of the genus Xanthoparmelia in South America, in order to determine reliable morphological and biochemical characters by which to recognize individual species and further to attempt to determine the evolutionary affinities of these taxa. Hundreds of novel chemical compounds (so called "lichen substances") have been identified in various lichens, and used at times as species markers. Dr. Nash will test whether these chemical types are stable features of particular species or whether the chemistry varies with environmental conditions under which the lichens grow. His taxonomic work on South American lichens will complement projects underway or completed on this genus for South Africa, Australasia, and North America, covering ultimately nearly 400 species.