Notes on the taxonomy of Pseudolysimachion sect. Pseudolysimachion (Scrophulariaceae) in Europe. I. P. incanum and P. spicatum

European species of Pseudolysimachion (Koch) Opiz (at least nine species) are divided into two sections: sect. Pseudolysimachion (typus: P. spicatum (L.) Opiz) and sect. Longifolia (Holub) Trávníček, stat. n. (typus: P. longifolium (L.) Opiz). A hybrid between P. incanum (L.) Holub s. str. and P. spicatum s. str. is described from Ukraine as P. ×blockianum Trávníček. Populations of P. incanum from the eastern part of the Pannonian Basin are classified as a separate subspecies, P. incanum subsp. pallens (Host) Trávníček. Geographical variation of P. spicatum was analysed, and new subspecies are described, subsp. lanisepalum Trávníček and subsp. fischeri Trávníček. Both new subspecies, recently usually included under the name “P. pallens” (sensu M. A. Fischer 1974), are considered to be products of repeated introgressive hybridization with P. incanum in the past. Geographical distribution of the type subspecies and of the two new subspecies is given. Several new combinations are proposed: Pseudolysimachion ×neglectum (Vahl) Trávníček (= P. incanum × P. longifolium), P. spicatum subsp. porphyrianum (Pavlov) Trávníček and P. s. subsp. viscosulum (Klokov) Trávníček. Lectotypes are designated for the names Veronica hybrida L., V. incana L. and V. pallens Host.