LINNÉ described two closely related Speedwells as Veronica longifolia and Veronica maritima. For long time the Central and South European plants have been regarded as Veronica longifolia. By OPIZ 1852 the plant has been transferred to the genus Pseudolysimachion, which since 2001 has been revoked again, because some plants of genus Veronica and Hebe (= bushy speedwells from America and New Zealand) have the attributes, too, due to that Pseudolysimachion had been separated.
In an article on the occasion of the nomination of the Longleaf Speedwell as 'wild flower of the year 2018' in Germany, VOLKER UNTERLADSTETTER explains in Jahrb. Bochumer Bot. Ver. 10: 246-257 (2019), that according to the geographically very widely comprising investigation of TRAVNICEK 2000 the Central and South European plants are belonging to LINNÉ's Veronica maritima with often whorled standing leaves (this more pronounced in Scandinavia than in Central Europe), 6 - 10 mm long petiole and acute teeth of the bracts, while LINNÉ's Veronica longifolia is an Asiatic-Siberian clan with oppositely standing leaves, shorter petiole and roundish teeth of the bracts, to which also Veronica pseudolongifolia is belonging, described by PRINTZ 1921 from Russia.