Catalpa lutea (Bignoniaceae), a new species from north, central, and east China

Catalpa lutea J.H.Wang, W.J.Ma & Z.Y.Li, a new species of Bignoniaceae from north, central, and east China, is described and illustrated. By combining recent morphological comparisons with phylogenetic analyses of nuclear single-nucleotide polymorphisms (SNPs) and the chloroplast genome, we demonstrate that C. lutea is readily distinguishable from its congeners, including Catalpa fargesii Bureau and other Chinese species of section Catalpa. A detailed morphological description, illustrations, and molecular data are provided. While conforming to sect. Catalpa in its typically ovate leaf blades, didynamous stamens, and five corolla lobes, C. lutea is unequivocally distinguished by its narrowly ovate crown, yellow heartwood, bright yellow anthers, filaments with purple dots, conspicuously thickened deep purple striations within the corolla tube, and floral spots exceeding 1 mm in diameter. Additional diagnostic characters include young foliage frequently flushed purple, mature leaves green with a purple tinge on occasion, and 3-4 nectaries at the leaf axils on the abaxial surface. The conservation status of this species is assessed as "Data Deficient" (DD) according to the IUCN Red List Categories and Criteria.