Hopper Stephen D
Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB UK.
Ann Bot. 2009 Aug;104(3):447-55. doi: 10.1093/aob/mcp090. Epub 2009 Apr 26.
The issue of determining the most appropriate rank for each accepted taxon fuels ongoing controversy throughout systematics. The particularly marked escalation of such issues in modern Australian orchid systematics merits examination, not only because of wider implications in taxonomy but also because of direct effects on studies of comparative biology and conservation management.
This paper briefly reviews the causes of recent taxonomic turmoil for Australian orchids and outlines new research opportunities and conservation implications arising from an improved understanding of their molecular phylogenetics.
DNA sequencing and intensified field work have contributed towards a much improved understanding of Australian orchid systematics. Great progress has been made in discerning monophyletic groups or clades. Fresh interpretations of morphological evolution have been made possible by comparisons with the results of DNA analyses. Significant conceptual shifts from polymorphic species concepts to biological and phylogenetic concepts have also elevated the discovery and description of new species. Consequently, over the past decade, the number of Australian orchid species recognized by taxonomists has risen from approx. 900 to 1200. Similarly, the number of genera recognized by some taxonomists has increased from 110 to 192, resulting in 45% of Australian species/subspecies being assigned a new generic epithet since 2000. At higher taxonomic levels, much of the recent controversy in Australian orchid systematics reflects a divergence in views about where to split and assign formal names within unequivocally monophyletic groups. Differences regarding typification in the case of Caladenia have added additional confusion and complexity. However, new insights into and research opportunities concerning speciation processes in orchids have arisen from the wealth of new data and discrimination of species. Robustly supported molecular analyses of most clades enable comparative biological studies of Australian orchids to be conducted as never before. Outstanding subjects exist for exploring pollination by sexual deception and understanding the intricacies of mycorrhizal relationships and orchid conservation biology.
确定每个被接受的分类单元最合适的等级这一问题，在整个系统分类学领域引发了持续不断的争议。此类问题在现代澳大利亚兰花系统分类学中尤为显著地升级，值得审视，这不仅是因为在分类学中有更广泛的影响，还因为对比较生物学和保护管理研究有直接影响。
本文简要回顾了澳大利亚兰花近期分类学混乱的原因，并概述了因对其分子系统发育有了更好理解而产生的新研究机会和保护意义。
DNA测序和强化的野外工作有助于大大增进对澳大利亚兰花系统分类学的理解。在识别单系类群或分支方面取得了巨大进展。通过与DNA分析结果进行比较，对形态进化有了新的解读。从多态物种概念到生物学和系统发育概念的重大观念转变，也提升了新物种的发现和描述。因此，在过去十年中，分类学家认可的澳大利亚兰花物种数量从约900种增加到了1200种。同样，一些分类学家认可的属数量从110个增加到了192个，自2000年以来，45%的澳大利亚物种/亚种被赋予了新的属名。在更高的分类学层面，澳大利亚兰花系统分类学近期的许多争议反映了在明确的单系类群中，对于何处进行划分并赋予正式名称存在观点分歧。在卡拉迪亚属的模式指定方面存在的差异，增加了更多的混乱和复杂性。然而，从丰富的新数据和物种鉴别中，产生了关于兰花物种形成过程的新见解和研究机会。对大多数分支的有力分子分析支持，使得澳大利亚兰花的比较生物学研究能够以前所未有的方式进行。存在着探索性欺骗授粉以及理解菌根关系和兰花保护生物学复杂性的突出课题。
