Platanthera guangdongensis and P. zijinensis (Orchidaceae: Orchideae), two new species from China: Evidence from morphological and molecular analyses

Two new Platanthera (Orchidinae, Orchideae, Orchidoideae) species, P. guangdongensis and P. zijinensis, from the Guang-dong Province in China are described and illustrated based on morphological and molecular analyses. Platanthera guangdongensis is leafless and resembles P. fujianensis, but it differs in terms of the shorter and/or smaller inflorescence, floral bract, dorsal sepal, lateral sepal, petal, and ligulate lip. Platanthera zijinensis is morphologically similar to P. minor, but it differs by the ovate-oblong to ovate floral bract, colour of flower, ovate dorsal sepal, oblong lateral sepal, ovate-oblong lip, and curved forward spur. The phylogenetic analyses based on nuclear ribosomal ITS and chloroplast (rbcL and matK) sequence data support that P. zijinensis and P. guangdongensis being sisters to each other and genetically sister to P. minor. The chloroplast rbcL of P. guangdongensis is a pseudogene, supporting its characterization as a holomycotrophic orchid.