Low genetic and morphological differentiation in the European species complex ofRosa sherardii,R. mollisandR. villosa(RosasectionCaninaesubsectionVestitae)

Abstract

The polyploid species complex of Rosa villosa sensu lato (Rosa section Caninae subsection Vestitae) consists of three morphologically similar polyploid species: R. sherardii, R. mollis and R. villosa. Whereas R. sherardii is distributed in central Europe, R. mollis and R. villosa represent a vicariant species pair occurring in northern Europe and in mountains of central and eastern Europe, respectively. In this study we analysed multiple data sets (morphology, cytology, microsatellites, AFLP and plastid DNA sequences) to re‐evaluate the systematics of these species and to examine whether cytological differences are reflected in the taxonomy and geographical distributions. Furthermore, these data sets were used to evaluate hypotheses explaining the vicariant distribution of R. mollis and R. villosa. None of these data sets revealed a clear‐cut differentiation between the species. Cytological and molecular data argued for a discrete taxonomic position of the predominantly pentaploid R. sherardii, but these data did not support a separation between the mostly tetraploid R. mollis and R. villosa. Population genetics revealed that samples of the latter species were assembled according to ploidy, but not to species affiliation or geographical distribution. Thus, we assume that the cytologically polymorphic original species had a continuous range prior to the last glaciation period and survived on nunataks or in non‐glaciated coastal regions in northern Europe, but that it failed to recover its former range after the retreat of the ice sheets. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174, 240–256.

Differentiation between two self-compatible cytotypes of Herbertia lahue (Iridaceae): evidence from genotypic and phenotypic variation

“…For H. lahue, the effect of polyploidy on the genetic structure of populations must also be considered. The polyploidy itself exerts a differentiating effect among populations, and it is known that recurrent polyploidy can create genetically distinct populations (Soltis and Soltis 2000;Soltis et al 2004;Kellner et al 2014). Moreover, as here other studies have demonstrated differences among cytotypes at genetic and morphological levels (Guldahl et al 2005;Keeler and Davis 1999;Tacuatiá et al 2012b;Khadivi-Khub et al 2014).…”

“…However, in other situations, the discriminating power of morphometric analysis is low. This was the case for other Iridaceae, for which morphometric analysis was unable to discriminate a species complex (Arafeh et al 2002;Sapir et al 2002;Saad and Mahy 2009) or alternative taxonomic group [e.g., in Rosa complex, Kellner et al (2014)]. In this study, despite morphometry being usless to infer relationships among cytotypes, combining some variables can be useful for preliminary and simple identification of cytotypes (Online Resource 3), particularly combining measurements (width and length) of the outer tepals.…”

“…Ser. (Kellner et al 2014). Additionally, polyploid species exhibit less inbreeding depression than their diploid parents, and can therefore tolerate higher levels of selfing (Soltis and Soltis 2000;Soltis et al 2004).…”

“…It is unclear whether other floral characters are suitable for distinguishing hexaploids and octoploids of H. lahue. Often, morphological studies on species that share cytotypic variation have led to the discovery of subtle differences between cytotypes, typically in terms of floral characteristics (Keeler and Davis 1999;Guldahl et al 2005;Tacuatiá et al 2012b;Kellner et al 2014). Cytotypes from H. lahue can possibly be discriminated by combining analysis of morphological and molecular characters.…”

Hybridization between the locally endangeredRosa spinosissimaandRosa mollisresults in the pentaploidRosa×sabiniiin western Norway

“…Well documented chromosome counts are known from western and continental Europe, but no records exist from Norway. Both R. mollis and R. sherardii belong to subsection Vestiate Christ within section Caninae, and the taxonomic separation of the species within this group is known to be challenging (Henker , Kellner et al ). The hybrid taxa R .…”