Hymenidium pilosum (Apiaceae) is a synonym of H. apiolens based on morphology and molecular data

Abstract

Hymenidium apiolens and H. pilosum have been recorded to co‐occur in the Himalayas, and it was found difficult to distinguish between them in the field. In this study, we reconstructed the phylogeny and estimated the genetic distance between individuals of H. apiolens, H. pilosum and related species based on nuclear ITS sequences, and rpl16 and rps16 introns, to determine the relationship between H. apiolens and H. pilosum. The analyses suggest that H. apiolens and H. pilosum are nested together, and that the ratio of genetic distance between them is smaller than that between individuals of Chamaesium spatuliferum, Hansenia forbesii or Ligusticum acuminatum. Furthermore, we found similar morphological characteristics of bracteoles, rays, petals and mericarps in H. apiolens and H. pilosum. Consequently, both molecular and morphological evidence supports that Hymenidium pilosum is a synonym of H. apiolens.