title: Herbarium-based studies on taxonomy, biogeography and ecology ofPsilochilus(Orchidaceae).
abstract: BACKGROUND
  Psilochilusis a poorly studied orchid genus distributed from southern Mexico to south-eastern Brazil. A taxonomic revision of this Neotropical endemic based on morphological data is presented.
  
  
  METHODS
  Over 170 dried herbarium specimens and flowers preserved in liquid ofPsilochiluswere analyzed. Morphological variation among examined taxa was described based on multivariate analysis. To evaluate the similarity between niches occupied by variousPsilochilusspecies ecological niche modeling (ENM) was applied. Species richness and the distribution patterns ofPsilochilusrepresentatives were analyzed based on squares of 5° latitude and longitude while similarities among floras between biogeographical units were measured using the Bray-Curtis index for presence/absence data.
  
  
  CONCLUSIONS
  A new species of theP. physurifolius-complex is described based on Central American material.Psilochilus crenatifoliusis reduced to the rank of variety asP. macrophyllusvar.crenatifolius. A key to 18 acceptedPsilochilusspecies is provided. The illustrations of perianth segments of all recognized taxa are presented. The climatic niches preferred by the particularPsilochilusrepresentatives are well separated based on ecological niche modeling analysis. Their distribution is limited mainly by the isothermality and temperature seasonality. The highestPsilochilusspecies richness is observed in the North Andean, Panamanian, Brazilian Planalto and Central American biogeographical provinces. A high level of endemism is observed in all those regions as well as Yungas biogeographical province. MostPsilochilusspecies occur in areas above 800 m of elevation. The populations were most often reported from the tropical rain forest and tropical moist deciduous forest.
authors.affiliation: Department of Plant Taxonomy and Nature Conservation/Faculty of Biology, University of Gdańsk, Gdańsk, Poland; Department of Biodiversity Research, Global Change Research Institute AS CR, Brno, Czech Republic.
authors.forename: Marta
authors.initials: M
authors.lastname: Kolanowska
authors.affiliation: Department of Molecular Evolution, University of Gdańsk , Gdańsk , Poland.
authors.forename: Aleksandra M
authors.initials: AM
authors.lastname: Naczk
authors.affiliation: Department of Invertebrate Zoology and Hydrobiology, University of Lodz , Łódź , Poland.
authors.forename: Radomir
authors.initials: R
authors.lastname: Jaskuła
keywords: Biodiversity; Ecological niche modeling; Neotropic ecozone; New species; Phytogeography; Psilochilus; Species richness; Taxonomy