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Morphological versus molecular delimitation of the genus Pleurothallis R.Br. (Orchidaceae)
Baláž, Přemysl ; Chumová, Zuzana (advisor) ; Figura, Tomáš (referee)
Pleurothallis R. Br is a genus of Neotropical orchids and one of many genera of a subtribe Pleurothallidinae. The genus Pleurothallis has undergone a very complex nomenclatural and taxonomic improvement over the last century, which is the main topic this thesis focuses on. Based on available literature, it compares two generic concepts of the genus Pleurothallis, a former morphological concept and a molecular concept, which reflects evolutionary history. The morphologically conceived Pleurothallis included (as of 1999) over 1500 more or less similar species divided into nearly 40 subgenera and over 20 subsections, sections and series. Some of the subgenera of morphologically conceived Pleurothallis have been raised to a generic level (e.g. Acianthera or Specklinia), others were merged with other already existent genera of Pleurothallidinae (such as Stelis). In some cases both generic concepts agree on which species they include; a genus Acianthera contains most of the species included in morphologically conceived Pleurothallis subgenus Acianthera. From the point of view of evolution, however, both genera are only distantly related. Much more frequent case is disagreement between both generic concepts, the most striking example can be seen when morphologically conceived Pleurothallis subgenus...
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