Polyphyly of <i>Tragopogon porrifolius</i> L. (Asteraceae), a European Native with Intercontinental Disjuncts

Abstract

Tragopogon L. comprises 150 species from Eurasia, with three diploids well established in North America (T. porrifolius, T. dubius, and T. pratensis). ITS, external transcribed spacer, and plastid sequence data indicate that T. porrifolius is polyphyletic. One lineage is phylogenetically well separated from other collections identified as T. porrifolius. This lineage is widespread in North America and Europe, includes the cultivated salsify, and has been considered T. porrifolius ssp. porrifolius. It is distinct from other T. porrifolius in having longer ligules and an additional set of chromosomal satellites. This “salsify” lineage is one parent (with T. dubius) of the North American allotetraploid T. mirus. Collections identified as T. porrifolius ssp. australis and ssp. cupani appear together in a clade well removed from ssp. porrifolius. These subspecies do not appear to have been introduced into North America. Available data suggest that ssp. cupani comprises both diploid and putative allotetraploid populations; hence, as currently described, this subspecies may encompass a previously unrecognized species. Additional samples of T. porrifolius not classified to subspecies, from both Europe and North America, form a third lineage and appear with collections of several species from Europe, including specimens identified as T. longirostris (which itself may not be monophyletic), another purple‐flowered Tragopogon. This lineage appears to represent an unrecognized species and indicates that an additional species of Tragopogon has been introduced into North America.