Staelia schumannii (Rubiaceae, Spermacoceae): An Old New Species from Bahia, Brazil, Overlooked for More than a Century

The new species Staelia schumannii was discovered through the analysis of historical collections associated with Staelia thymbroides (equivalent to Psyllocarpus thymbroides). The rediscovery of the missing type of S. thymbroides has shed light onto its identity, as well as onto the yet undescribed S. schumannii. In order to clarify their circumscriptions, both species are described and illustrated, and an identification key for all Brazilian Staelia is provided.