Critical notes on Spiradiclis purpureocaerulea H. S. Lo (Rubiaceae) from Vietnam

Based on a careful examination of the voucher specimens, the newly recorded Spiradiclis purpureocaerulea H. S. Lo from Vietnam was confirmed to be a misidentification of S. coccinea H. S. Lo. Coincidentally, Spiradiclis coccinea is a species previously known only from China, and represents a new record for the flora of Vietnam. True specimens of S. purpureocaerulea were collected by the authors in Thanh Hua Province (Vietnam) in 2017. Therefore, we report S. coccinea and S. purpureocaerulea as new records for the flora of Vietnam here. Detailed descriptions and color photographs of the two species and a key to the five species of Spiradiclis in Vietnam are also provided.