resolving generic limits in a large group of small orchids









This study expands our previous work (especially subtribes Maxillariinae, Oncidiinae, Zygopetalinae, and Stanhopeinae) to the subtribe Pleurothallidinae.


We are submitting our proposal to reconstruct the phylogenetic relationships of approximately 3,500 orchid species, representing subtribe Pleurothallidinae. We have submitted the proposal to the National Science Foundation for this project and this site contains the main parts of that proposal.

In recent years, orchid systematists have made great progress in clarifying evolutionary relationships among orchid genera, based largely upon cladistic analyses of both molecular and morphological/anatomical data sets. A well-supported outline of tribal and subtribal relationships is quickly emerging, limited primarily by the rate that rare taxa can be collected and analyzed. As such broad scale studies progress, it is becoming clear that one of the most daunting remaining tasks will be the phylogenetic revision of very large, species rich genera (e.g., Bulbophyllum, Epidendrum, Maxillaria, Pleurothallis). An even greater problem is that few taxonomists have the years of intensive study and breadth of knowledge to work with these large taxa. For example, few taxonomists are able to accurately identify a randomly-chosen Pleurothallis or Maxillaria species. Existing keys and subgeneric classifications are incomplete and are based upon admittedly artificial classifications.

To attempt a modern molecular and morphology-based phylogenetic revision of these huge genera, a broad collaboration is required among alpha-taxonomists who have intensive, detailed knowledge of the species, their variation and nomenclature, and molecular systematists who can generate and analyze the large data sets necessary to resolve these genera. We have assembled such a collaborative group, which includes: 1) herbarium/field botanists with years of study and deep knowledge of these species and their nomenclature; 2) orchid molecular systematists with experience in collecting and analyzing large combined DNA data sets; 3) pollination biologists; and 4) natural product chemists experienced in analyzing floral rewards.

Why study Orchidaceae? With more than 800 genera and 25,000 species, Orchidaceae are the largest and most diverse family of plants. Orchids represent a significant branch in the tree of life, with more species than vertebrates (excluding bony fishes). Although new orchid species continue to be described, a solid alpha-taxonomic framework exists in the form of a collaborative provisional checklist of all genera and species. No other group of plants attracts such widespread interest from professional botanists, horticulturists, and the general public alike.

The subtribe Pleurothallidinae contains 90-150 genera and over 7,400 species names. Even allowing for a number of these names being synonyms, we estimate over 3,500 species in the group.

This site contains information from our grant proposal and includes: 1) the Project Summary; 2) the Project Description; 3) References; 4) the Management Plan; 5) a list of our collaborators; 6) a link to a list of all known species of Pleurothallidinae (the Kew Orchid Checklist of all currently recognized genera and species) 7) cladograms from published and unpublished studies of the molecular systematics of various groups will be added as we develop this site; and 8) links to a number of useful sites.

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Page last updated: 30 March 2006

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