Taxonomic review of Lepidium ruderale (Brassicaceae) in Korea

The current status of Lepidium ruderale L. is uncertain in Korea. This alien species was previously reported as a new record of the Korean flora and placed under L. ruderale. Although some taxonomists have suggested that it belongs to another Lepidium taxon, no conclusions have been reached. Therefore, in this study, the holotype and protologue of L. ruderale were obtained and carefully examined. The description of this species is as follows: basal leaves are 1–3 pinnate; cauline leaf blades are linear to lanceolate and entire and ciliate; petals are absent or rudimentary; flowers have two stamens; and fruits are winged at the apex, have an apical notch, and are glabrous. These features distinguish it from other Lepidium species. Examination of numerous specimens and analysis of multiple characteristics demonstrated that the voucher specimens of L. ruderale belong to L. pinnatifidum Ledeb. Therefore, L. ruderale is not distributed in Korea.