Exploring patterns of variation within the central-European Tephroseris longifolia agg.: karyological and morphological study.

Tephroseris longifolia agg. is an intricate complex of perennial outcrossing herbaceous plants. Recently, five subspecies with rather separate distributions and different geographic patterns were assigned to the aggregate: T. longifolia subsp. longifolia, subsp. pseudocrispa and subsp. gaudinii predominate in the Eastern Alps; the distribution of subsp. brachychaeta is confined to the northern and central Apennines and subsp. moravica is endemic in the Western Carpathians. Carpathian taxon T. l. subsp. moravica is known only from nine localities in Slovakia and the Czech Republic and is treated as an endangered taxon of European importance (according to Natura 2000 network). As the taxonomy of this aggregate is not comprehensively elaborated the aim of this study was to detect variability within the Tephroseris longifolia agg. using methods of plant systematics (multivariate morphometrics of 525 individuals/33 populations based on 49 characters, DAPI flow cytometry of 98 individuals/33 populations). The relative DNA content at the homoploid level (2n ~ 6x ~ 48) varied by 25.8% and significant taxa-specific differences were confirmed among plants of T. l. subsp. pseudocrispa, subsp. gaudinii, subsp. brachychaeta and a group consisting of T. l. subsp. moravica and subsp. longifolia. The morphometric study indicated six morphotypes roughly corresponding to the previously distinguished subspecies. The exceptions were populations traditionally assigned to T. l. subsp. longifolia, for which two distinct morphotypes with different geographic origins were identified: Alpine morphotype and Pannonian morphotype. In general, the differences in DNA content and morphology argue for a classification at the species level for plants of T. l. subsp. brachychaeta, while differences among other morphotypes fit a subspecific level. Surprisingly, Pannonian populations of T. l. subsp. longifolia are morphologically closer to populations of the Western-Carpathian endemic subsp. moravica than to Alpine populations of nominate subspecies. Based on this, the taxonomic position of Pannonian morphotype and subsequently the endemic status of T. l. subsp. moravica require further study. A key for identifying the taxa and morphotypes of Tephroseris longifolia agg. in central Europe is presented.