Grob, Philipp Markus

Petersen, Andreas Friis

Increasing conservation efforts depend upon taxonomy to determine which key species and habitats should be protected. However, many classification systems rely heavily on morphological characters, especially within the Orchidaceae family. Over the past decades, the Dactylorhiza genus has been severely split by certain authors, which assume genetic variation to be the only factor governing morphological variation. However, it is known that plants are able to alter their phenotype without changes to the genotype via phenotypic plasticity. Ecophenotypy, which is environmentally governed phenotypic plasticity, may be a possible contributor to morphological variation and has not yet been studied in Dactylorhiza. This case study investigated the possibility of ecophenotypy in four broadly delimited Dactylorhiza species on the basis of the following question: can morphological variation in Dactylorhiza incarnata largely be explained by genetic variation, or does it involve significant amounts of ecophenotypy? Morphometric data divided into seven vegetative and four floral characters in Northern European Dactylorhiza populations was analyzed using the linear mixed-effects model. The between- and within-populations coefficient of variation (CV) of D. incarnata with a remarkably low genetic variation were contrasted to three species with a comparatively high genetic variation. Firstly, D. incarnata did not express a lower morphological variation in neither between- nor within-population CV. Secondly, the within-populations CV showed more differentiated variations than for between-populations. Thirdly, D. traunsteineri showed a lower variation in within-populations CV compared to at least one study species in as many characters as D. incarnata. Lastly, floral characters were observed to vary significantly less than vegetative characters, and D. incarnata varied less in all floral characters but only in a few vegetative characters compared to at least one other study species. The results of this study suggest that ecophenotypy in D. incarnata is prevalent and even when considering D. traunsteineri apparently showing the least amount of ecophenotypy, fine-meshed morphology-based classifications for Dactylorhiza are not justified. Should demarcation of Dactylorhiza depend on morphology, floral characters would prove to be the most reliable

Roskilde Universitet

Towards a holistic approach to orchid taxonomy - A case study on the morphological variation of Dactylorhiza incarnata: A case study on the morphological variation of Dactylorhiza incarnata

Towards a holistic approach to orchid taxonomy - A case study on the morphological variation of Dactylorhiza incarnata: A case study on the morphological variation of Dactylorhiza incarnata

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Roskilde Universitet