Cytogenetic evidence for a new genus of Triticeae (Poaceae) endemic to the Iberian Peninsula: description and comparison with related genera

Abstract

Thinopyrum curvifolium, a halo-gypsophyte endemic to the Iberian Peninsula, has an uncertain cytogenetic composition. Moreover, it is often confused with other species of the genus due to morphological resemblance. In this study, we analyse its genomic composition using in situ hybridization and study lodicule morphology and foliar anatomy, to identify distinguishing traits of the species in comparison with the remaining representatives of Thinopyrum in the Iberian Peninsula and the Balearic Islands. In situ hybridization data support the genomic formula 2n = 4x = 28, EbP. Lodicule morphology and foliar anatomy proved helpful in characterizing the species. These new discoveries, in addition to the macromorphological data compiled, support the contentions that (1) T. curvifolium should be segregated from Thinopyrum sensu D.R.Dewey, and (2) a new cytogenetically based genus should be proposed in order to classify the species properly according to the cytogenetically based criteria traditionally proposed for the classification of Triticeae. Therefore, we hereby propose a new genus named Pauneroa gen. nov., including the new nomenclatural combination Pauneroa curvifolia comb. nov., and provide a detailed iconography of the plant, macroscopically comparing the genus with closely related genera.