The Morphological and Genetic Variation in the Polymorphic Species Picris hieracioides (Compositae, Lactuceae) in Europe Strongly Contrasts with Traditional Taxonomical Concepts
Abstract
The present paper provides a large-scale taxonomic revision of Picris hieracioides, a highly polymorphic and taxonomically controversial species in Europe. Altogether, 104 populations were sampled and examined using multivariate morphometrics and genetic amplified fragment length polymorphism (AFLP) data.
Two morphotypes are delimited, the 'higher altitude' and the 'lower altitude' morphotypes, which are congruent with the two main genetic groupings revealed by AFLP markers. It is concluded that two subspecies should be recognized within this species, P. hieracioides subsp. hieracioides, comprising annual to biennial plants occupying dry, sunny, often man-made habitats at low altitudes, and P. hieracioides subsp. umbellata, being mostly a short-lived perennial that grows in mesic, semi-natural or natural habitats at higher altitudes.
This infraspecific treatment strongly contrasts with the traditional taxonomic concepts, which recognize up to 10 subspecies of P. hieracioides in Europe. An identification key and a nomenclatural account are presented, including the designation of lectotypes.
Picris hieracioides harbors large genetic variation, and two lineages can be recognized within each subspecies, most likely reflecting their glacial survival and postglacial colonization routes. Long-distance dispersals, anthropogenic introductions and recent spread are suggested to have shaped their genetic structure as well.
A Balkan endemic P. hispidissima, although morphologically and ecologically well defined, appears to be genetically close to P. hieracioides.