Contrast in levels of morphological versus molecular divergence between closely related Eurasian species of Platanthera (Orchidaceae) suggests recent evolution with a strong allometric component

@article{Bateman2012ContrastIL,
  title={Contrast in levels of morphological versus molecular divergence between closely related Eurasian species of Platanthera (Orchidaceae) suggests recent evolution with a strong allometric component},
  author={Richard M. Bateman and Karen E. James and Paula J. Rudall},
  journal={New Journal of Botany},
  year={2012},
  volume={2},
  pages={110 - 148}
}
Abstract We consider the conceptual relationship between pollinator specfificity, genetic isolation and species delimitation, critiquing Darwin’s (1877) hypothesis that differential placement of pollinia on the probosces and eyes of sphingid moths explained the divergence of the Eurasian orchids Platanthera bifolia and P. chlorantha — species that have similar geographic distributions, habitat preferences and flowering times. Subsequent workers have developed Darwin’s initial hypothesis into an… 
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Speciation via floral heterochrony and presumed mycorrhizal host switching of endemic butterfly orchids on the Azorean archipelago.
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Although morphological evidence suggests two invasions of the islands from NW Africa and/or SW Europe, ITS data imply only one, limited genotypic divergence among the three species compared with greater phenotypesic divergence suggests comparatively recent speciation.
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TLDR
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Darwin’s legacy in Platanthera: are there more than two species in the Platanthera bifolia/chlorantha group?
TLDR
The finding of three distinct lineages within the bifolia/chlorantha group necessitates a thorough reanalysis of reported taxa and a reevaluation of the understanding of their distribution, ecology and evolution.
Characterization of sympatric Platanthera bifolia and Platanthera chlorantha (Orchidaceae) populations with intermediate plants
TLDR
This study provided a much more detailed picture of the genetic structure of a sympatric zone between two closely allied species and supports the hypothesis that intermediate morphotypes in sympatry could reflect an adaptive evolution in response to local pollinator-mediated selection.
Artificial crossing and pollen tracking reveal new evidence of hybridization between sympatric Platanthera species
TLDR
Results showed weak reproductive isolation between P. bifolia and P. chlorantha and may refer to the early stages of speciation of the species.
Can phenotypic selection on floral traits explain the presence of enigmatic intermediate individuals in sympatric populations of Platanthera bifolia and P. chlorantha (Orchidaceae)?
TLDR
Phenotypic selection in a sympatric population of two orchid species, Platanthera bifolia and P. chlorantha, is estimated to conclude that, despite a significant selective pressure on some phenotypic traits, the presence of individuals with intermediate phenotype is not due to selection.
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