Orychophragmus yangii sp. nov. (Brassicaceae), a new species from Shaanxi, China

A new species, Orychophragmus yangii sp. nov., from the Loess Plateau of Shaanxi Province, China, is described and illustrated. This species differs clearly from all other Orychophragmus species in the following traits: whole plant glabrous; leaves varying from simple to pinnatifid but never lyrate; pinnatifid leaves with lobes divided or not; simple leaves widest at the base; sepals green; petals white; fruit narrowly linear, terete, and glabrous; rostra of fruit 2-4 mm long. Molecular phylogenetic analyses based on plastid genomic data and nuclear ribosomal RNA genes showed that the new species represents the first divergent lineage in the genus Orychophragmus. The chromosome number of the new species is 2n = 24.