Karyo-Taxonomic Study of the Genus Pseudolysimachion (Scrophulariaceae) in the Czech Republic and Slovakia

Flow cytometry was used to determine ploidy levels in the Czech and Slovak taxa of the genus Pseudolysimachion (W.D.J. Koch) Opiz (= Veronica auct. p.p., Scrophulariaceae). In total, 123 populations from the Czech Republic, Slovakia, Ukraine (one locality), Austria (one locality) and Hungary (one locality) were analyzed. In P. maritimum (L.) Á. Löve et D. Löve and P. spicatum (L.) Opiz, two cytotypes were found: diploid (2n=2x=34) and tetraploid (2n=4x=68). In both species the tetraploid cytotype predominated (P. maritimum: 41 tetraploid populations out of 45; P. spicatum: 57 tetraploid populations out of 58). The two cytotpes of P. maritimum have no taxonomic significance because ploidy level is not obviously correlated with morphology, distribution pattern or ecology. Tetraploid populations of P. spicatum belong to two morphologically different subspecies, subsp. spicatum and subsp. fischeri Trávníček. The diploid cytotype (one population only) should be provisionally classified as a third subspecies of P. spicatum, which is morphologically similar to the Asian subsp. porphyrianum (Pavlov) Trávníček. Only diploid plants (2n=2x=34) of P. orchideum (Crantz) Wraber were found; all 13 populations that were analyzed belong to P. orchideum s.str. One diploid population sample of P. spurium subsp. foliosum (Waldst. et Kit.) Holub (2n=2x=34) and one tetraploid sample of P. incanum subsp. pallens (Host) Trávníček (2n=4x=68) were also analyzed. In addition, three tetraploid populations of hybrid origin were investigated: P. maritimum × P. spicatum subsp. spicatum (one population) and P. maritimum × P. spurium subsp. foliosum (two populations). While hybrid plants of P. maritimum × P. spicatum arose from tetraploid parental species, plants of P. maritimum × P. spurium probably resulted from a cross between tetraploid P. maritimum and diploid P. spurium. The putative origin and evolutionary importance of polyploids in the Pseudolysimachion are discussed.