Taxonomic Revision of Selected Sonoran Lichen Families

9707714纳什地衣是真菌和藻类的共生群落，通常根据伙伴关系中的真菌有机体进行识别和分类。它们广泛存在于土壤、岩石和附生植物上，有时也很丰富。数千种地衣的分类很复杂，因为它们在博物馆收藏品中的代表性很差，而且体积很小，导致人们把重点放在几个被认为是用于区分的“关键”字符上。不幸的是，现在人们普遍认为，这些关键特征中的许多已经在不同的地衣类群或谱系中多次进化；因此，地衣分类需要更多的标本，并更密切地关注新的形态和分子特征的获得。对于北美索诺兰沙漠和邻近的地中海气候加州部分地区的大型地衣“植物群”，托马斯·纳什教授组建了一个由大约50名专家组成的国际团队，从学生到高级研究人员，完成了对疑似1700种地衣的分类清点。四个在分类学上有麻烦的大属，Arthonia，Buellia，Lecania和Solenopsora，是野外工作、博物馆研究和分类学修订的主要目标；第五个属，Verrucaria，将接受初步研究。这将与年轻的欧洲工人一起完成，他们专门研究这些群体的地中海近亲，他们可以测试物种限制和针对北美群体中发现的变异进行诊断。在世界大多数地区，地衣的生物多样性和分类仍然鲜为人知，其研究的传统强调由一到两名专家进行狭隘的国家或区域研究。纳什教授的国际同事联盟专注于北美的一大片沙漠地区，在分类学上与世界地中海气候区有亲缘关系，他们提出了两种现代方法，有望给地衣研究带来革命性的变化。第一，来自国际人才库的专家的协作工作；第二，从全球角度比较形态和解剖特征，以评估有助于鉴定和高级分类的分类特征的可靠性。

9707714 Nash Lichens are symbiotic associations of a fungus and an alga, and they are usually identified and classified on the basis of the fungal organism in the partnership. They occur widely and at times abundantly on soil, rocks, and as epiphytes. The classification of the several thousands of species of lichens is complicated by their poor representation in museum collections and their small size, resulting in an emphasis on a few supposed "key" characters for discrimination. Unfortunately, it is now widely accepted that many of these key features have evolved multiple times, in different groups or lineages of lichens; thus, lichen classification requires more specimens and closer attention to the acquisition of new morphological and molecular characters. For the large lichen "flora" of the North American Sonoran desert and adjacent parts of California with a mediterranean type climate, Prof. Thomas Nash has assembled an international team of 50 or so specialists, students to senior researchers, to complete a taxonomic inventory of the suspected 1700 species of lichens. Four large and taxonomically troublesome genera, Arthonia, Buellia, Lecania, and Solenopsora, are the main targets for field work, museum study, and taxonomic revision; a fifth genus, Verrucaria, will receive preliminary study. This will be accomplished in conjunction with young European workers who have specialized on the mediterranean relatives of these groups, and who can test species limits and diagnoses against the variation to be found in the North American groups. The biodiversity and classification of lichens remain poorly known in most parts of the world, and the research tradition for their study has emphasized narrow national or regional studies by one or two specialists. Prof. Nash's international consortium of colleagues, focusing on a large desert region of North America, with taxonomic relatives in mediterranean climates of the world, promotes two modern approaches that promise to revolutionize the study of lichens. First, collaborative work by specialists drawn from an international pool of talent; second, a global perspective in comparisons of morphological and anatomical characters to assess the reliability of taxonomic features useful for identification and upper-rank classification.