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... Gymnadenia conopsea var. friesica always grows in damp coastal dunes, whereas Gymnadenia conopsea var. densiflora is to be found in wet chalk meadows with high vegetation, and never in coastal dune areas. Typical specimens are illustrated in KREUTZ & DEKKER (2000: 58-61)." Further typical specimens from the Frisian Islands are illustrated in Fig. 1 and Texel, it now appears to be extinct in Germany (KREUTZ & LEWIS (2015: ...
Citations
... friesica Schlechter by Kreutz and Lewis (2015), who argued that this taxon probably also occurs in Ireland and Walesspecifically, in the Kenfig duneslack population that provided one of the morphometric datasets for the present study, as well as DNA samples analysed and discussed by Bateman et al. (2018b) and Brandrud et al. (2019). This taxon was reclassified by Lewis (2015) with impressive alacrity as G. densiflora var. friesica (Schlechter) L. Lewis, following review of the few biosystematic data available at the time. ...
... Sadly, the truthful answer here remains 'We don't know'. To the best of our knowledge, there is presently only one serious contender: 'friesica', supposedly endemic to dune slacks in the Frisian Islands (Vermeulen, 1958;Dekker, 1992;Kreutz & Dekker, 2000;Kreutz & Lewis, 2015;Lewis, 2015;Delforge, 2016;Bateman et al., 2018b;Bateman & Denholm, 2019). The possibility that the Kenfig population analysed here was attributable to friesica was first suggested on the basis of in situ visual inspection of Frisian plants by Kreutz (2008). ...
Circumscriptions of both the genus Gymnadenia and the 11–27 species that it contains are highly controversial. These Eurasian terrestrial orchids are nectar-rewarding and pollinated primarily by Lepidoptera. Opinions expressed on the number of species occurring in the British Isles range from one to four, though there exists broad agreement that at least three recognizable, ecologically differentiated taxa are widespread. Here, we use a large-scale morphometric survey of these supposedly ‘cryptic’ taxa to determine whether phenotypic differentiation exists alongside their documented genotypic and ecological differentiation, seeking the most diagnostic morphological characters. Ten Gymnadenia plants were measured in each of 29 populations that encompassed the entire taxonomic range and geographic distribution of the genus within the British Isles. Results were subjected to detailed multivariate and univariate analyses, and interpreted in the context of molecular phylogenies, including a bespoke Europe-wide nrITS phylogeny that includes 17 plants sampled across Britain and Ireland. Floral micromorphology was investigated through scanning electron microscopy. Ecotypes occurring respectively in calcareous grasslands (G. conopsea s.s.), acid heaths (G. borealis) and calcareous to neutral marshes (G. densiflora) are subtly but reliably distinct, both morphologically and molecularly, though locally their morphological distinctiveness is somewhat weakened by the occurrence of infrequent populations in dune slacks and chalk downs that are intermediate in phenotype between the grassland and marsh ecotypes ('subsp. cf. friesica'). A polythetic taxonomic key emphasizes the characters and character-state ranges that are demonstrably the most diagnostic. Given that they are reliably genetically differentiable, and individuals can be distinguished with ∼85% confidence using morphological characters such as flower dimensions, depth of flower colour, and leaf number and size, we uphold our previous arguments that the three ecotypes merit species-level recognition. In the continued absence of field sequencing devices, identification is best attempted through quantitative examination of morphology focused at the population level, rejecting records of isolated plants. Despite their strong morphological similarity, genus-wide molecular data show that the British species are not each other's closest relatives. Gymnadenia borealis remains one of only three orchid species putatively endemic to the British Isles.
Prompted by concurrent completion of the latest plant atlas for Britain and Ireland, the orchid flora of these islands is reviewed in detail, focusing on 21st century progress in both systematics research and formal conservation categorisation under IUCN criteria. DNA-based phylogenies consistently circumscribe monophyletic groups that constitute obvious genera, though relationships among those genera remain less certain and resistance to phylogenetic classification persists. Comparison of species circumscription studies in critical groups such as Dactylorhiza , Gymnadenia , Platanthera , Epipactis and Orchis shows that most of the recent progress has been achieved using DNA-based techniques, which have also greatly increased understanding of associated mycorrhizae. Most morphological studies remain disappointingly traditional, squandering opportunities for morphometric studies that identify discontinuities between species, allow comparison of rates of morphological and molecular evolution, and underpin accurate quantitative descriptions designed to aid identification. Possibly only one of the 53 species recognised as native is still viewed as endemic. Conventional views on the significance of both pollinator specificity and quantitative seed output as the preferred measure of fitness are questioned, and mycorrhizae are explored as possibly under-rated ecological filters. Comparison of species distributions in successive Atlases suggests diverse patterns of change that reflect a combination of habitat modification, climate change and, in a few cases, improved identification skills. Ecologically tolerant lowland species such as Ophrys apifera and Dactylorhiza praetermissa are migrating northward rapidly, while the genus Serapias appears to be mounting a cross-Channel invasion. Most formal Red-Listing categorisations, and the underlying IUCN criteria, are supported for decisions made within the British Isles, but unfortunately, they have translated poorly into the equivalent European and Global lists. Within Britain, the Data Deficient category has been employed too frequently and illogically; ironically, it is sometimes used to penalise species for having been the subjects of serious research. Far from being "complete", the present consensus view on the taxonomy and evolution of the glacially impoverished British and Irish flora is judged both parochial and complacent. Reinvigorated UK-based research programmes that integrate quantitative morphological and molecular studies of British and Irish natives in a European context are urgently needed.
The digitate-tubered clade (Dactylorhiza s.l. plus Gymnadenia s.l.) within subtribe Orchidinae is an important element of the North-temperate orchid flora and has become a model system for studying the genetic and epigenetic consequences of organism-wide ploidy change. Here, we integrate morphological phylogenetics with Sanger sequencing of nrITS and the plastid region trnL-F in order to explore phylogenetic relationships and phenotypic character evolution within the clade. The resulting morphological phylogenies are strongly incongruent with the molecular phylogenies, instead reconstructing through parsimony the genus-level boundaries recognised by traditional 20th Century taxonomy. They raise fresh doubts concerning whether Pseudorchis is sister to Platanthera or to Dactylorhiza plus Gymnadenia. Constraining the morphological matrix to the topology derived from ITS sequences increased tree length by 20%, adding considerably to the already exceptional level of phenotypic homoplasy. Both molecular and morphological trees agree that D. viridis and D. iberica are the earliest-diverging species within Dactylorhiza (emphasising the redundancy of the former genus Coeloglossum). Morphology and ITS both suggest that the former genus Nigritella is nested within (and thus part of) Gymnadenia, the Pyrenean endemic 'N.' gabasiana apparently forming a molecular bridge between the two radically contrasting core phenotypes. Comparatively short subtending molecular branches plus widespread (though sporadic) hybridisation indicate that Dactylorhiza and Gymnadenia approximate the minimum level of molecular divergence acceptable in sister genera. They share similar tuber morphologies and base chromosome numbers, and both genera are unusually prone to polyploid speciation. Another prominent feature of multiple speciation events within Gymnadenia is floral paedomorphosis. The 'traditional' morphological and candidate-gene approaches to phylogeny reconstruction are critically appraised.
