J. Jpn. Bot. 90: 179–191 (2015) Variation in Veronicastrum sibiricum (Plantaginaceae) Hiroyoshi OHASHI Herbarium TUS, Botanical Garden, Tohoku University, Sendai, 980-0862 JAPAN E-mail:
[email protected] (Accepted on 9 January 2015) Morphological variation of Veronicastrum sibiricum (L.) Pennell and V. japonicum (Nakai) T. Yamaz. with their infraspecific taxa were examined in herbarium specimens. Morphological differences used for delimitation of these taxa fall within a continuous range of variation. Veronicastrum sibiricum is recognized here as a single polymorphic species composed of five forms including two new combinations: f. glabratum (Nakai) H. Ohashi and f. humile (Nakai) H. Ohashi. Veronicastrum sibiricum var. yezoense, V. sibiricum var. zuccarinii, Veronicastrum japonicum, and V. japonicum var. australe were indistinct from V. sibiricum var. sibiricum. A bibliographic enumeration is presented for each name. Each lectotype was designated for Veronica sibirica var. glabra Nakai, Veronica sibirica var. japonica f. latifolia Nakai, and Veronica sachalinensis T. Yamaz. Key words: Lectotypification, morphological variation, Plantaginaceae, polymorphic species, Veronica, Veronicastrum japonicum, Veronicastrum sibiricum. Veronicastrum sibiricum (L.) Pennell This paper aims to reevaluate taxonomic status (Plantaginaceae) is known in Japan, China, of V. sibiricum and its related taxa based on Korea, E. Siberia and Far Eastern Russia. The examination of herbarium specimens. species shows a wide range of morphological variation mainly in degree of hairiness on the Taxonomic history of Veronicastrum rachis of inflorescences and the surfaces of sibiricum in Japan leaves, length of the pedicel or relative length Thunberg (1784) recorded Veronica virginica between the pedicel and the calyx, shape of the L. from Nagasaki, Osaka and others in Japan apex of corolla-lobes, and number of leaves with Japanese names “Iaponice: Ireisin, vulgo at a node of the stem.