A second species of Pseuduvaria in China: the identity of the enigmatic species Meiogyne kwangtungensis

Abstract

Meiogyne kwangtungensis is a rare species endemic to Hainan, China, known just from two fruiting collections made in the 1930s. Although it was published under the name Meiogyne in 1976, it was suggested that it might be better placed within Pseuduvaria or Mitrephora. For decades, this species was never collected again, thus its true generic affinity remained unresolved due to the lack of flowers. During a field exploration in Hainan, we re-discovered this species and collected a flowering specimen for the first time. The flower immediately confirmed its affinity with Pseuduvaria. Phylogenetic analyses of five chloroplast regions (psbA-trnH, trnL-F, matK, rbcL, and atpB-rbcL; ca. 4.2 kb, 70 accessions) also unambiguously placed Meiogyne kwangtungensis in the Pseuduvaria clade (PP = 1.00, ML BS = 99%). Morphologically, it is most similar to P. multiovulata which is endemic to Myanmar and Thailand, both with often-paired flowers, long pedicels and short peduncles, and often 1–2 monocarps. However, it differs in having smaller flowers with kidney-shaped glands on the inner petals, fewer stamens and carpels, smaller ovoid monocarps with an apicule and fewer seeds. On the basis of the combined molecular phylogenetic and morphological data, we propose a new combination, Pseuduvaria kwangtungensis (P.T.Li) Qing L.Wang & B.Xue. A full description including floral characters and a color plate are provided here for this species. A key to species in the genus Pseuduvaria in China is also provided.