Hemiboea yongfuensis (Gesneriaceae): a cryptic and critically endangered new species from North Guangxi, China

The limestone region of southern China is a biodiversity hotspot from where numerous rare new species have been or are being described. Here, Hemiboea yongfuensis, a new species of Gesneriaceae from a limestone hill in Guilin, North Guangxi, southern China is described and illustrated. It is similar to H. subcapitata and H. pterocaulis in morphology and coexists with both of them in the same limestone hill, but can be distinguished from the latter two by its quadrilateral stem without winged edges, corolla outside light pink and sparsely glandular-pubescent and pale pink calyx which is 5-lobed from base, as well as by molecular data from trnL-F and ITS. We provide detailed information, including morphological descriptions, illustrations, diagnostic comparisons and molecular phylogenetic affinities of the new species.