Rubiacearum Americanarum Magna Hama XXXIII: The New Group Palicourea sect. Didymocarpae with Four New Species and Two New Subspecies (Palicoureeae)

Morphological and molecular studies show that many of the species classified in Psychotria L. subg. Heteropsychotria Steyerm. belong to Palicourea Aubl. Accordingly, most of the species of Psychotria sect. Didymocarpos Steyerm. plus several additional species are transferred to the new Palicourea sect. Didymocarpae C. M. Taylor; however, the type species of Steyermark's section, Psychotria bahiensis DC., does not have the diagnostic fruit and pyrene morphology and is excluded. Palicourea sect. Didymocarpae includes 17 species found from central Mexico and the Antilles to northeastern South America and Bolivia and is diagnosed by its didymous fruits with two subglobose pyrenes that are smooth abaxially and have thin-textured walls. New combinations are made: Palicourea boraginoides (Dwyer) C. M. Taylor is based on Psychotria acuminata Benth. subsp. boraginoides Dwyer; Palicourea candelabrum (Standl.) C. M. Taylor is based on Psychotria candelabrum Standl.; Palicourea ceratantha (Standl.) C. M. Taylor is based on Psychotria ceratantha Standl.; Palicourea compta (Standl.) C. M. Taylor is based on Psychotria compta Standl.; Palicourea cuspidata (Bredem. ex Schult.) C. M. Taylor is based on Psychotria cuspidata Bredem. ex Schult.; Palicourea cuspidulata (K. Krause) C. M. Taylor is based on Cephaelis cuspidulata K. Krause; Palicourea huampamiensis (C. M. Taylor) C. M. Taylor is based on Psychotria huampamiensis C. M. Taylor; Palicourea jauaensis (Steyerm.) C. M. Taylor is based on Psychotria jauaensis Steyerm.; Palicourea pandensis (Standl.) C. M. Taylor is based on Psychotria pandensis Standl.; Palicourea rhodothamna (Standl.) C. M. Taylor is based on Psychotria rhodothamna Standl.; Palicourea spicata (Kuntze) C. M. Taylor is based on Uragoga spicata Kuntze, a replacement name for the illegitimate name Psychotria spicata Mull. Arg.; and Palicourea subcuspidata (Mull. Arg.) C. M. Taylor is based on Psychotria subcuspidata Mull. Arg. and includes Psychotria cornigera Benth., recognized as a separate species from Psychotria bahiensis. Flowers are described for the first time for Palicourea candelabrum, and the circumscriptions of Palicourea acuminata (Benth.) Borhidi, Palicourea compta, and Palicourea rhodothamna are revised. The new species Palicourea andina C. M. Taylor is found in western Panama and the Andes of Colombia, Ecuador, Peru, and Bolivia and distinguished from Palicourea cuspidata by its corollas that lack abaxial horns on the lobes; two subspecies are separated, Palicourea andina subsp. panamensis C. M. Taylor in Panama and the typical subspecies in the Andes. The new species Palicourea diminuta C. M. Taylor of the Guianas and adjacent northeastern Brazil is distinguished by its small straight corollas. The new species Palicourea madidiensis C. M. Taylor of southern Peru and Bolivia differs from Palicourea acuminata in its corolla lobes with small abaxial projections and its habitat at higher elevations. The new species Palicourea sanluisensis C. M. Taylor of northwestern Colombia differs from Palicourea acuminata in its stiff-textured leaves, corollas with small abaxial thickenings on the lobes, and habitat on sandstone substrates. The new subspecies Palicourea cuspidata subsp. occidentalis C. M. Taylor is found in mountain forests of Colombia and northern Ecuador and is disjunct from the typical subspecies. The names Cephaelis cuspidulata and Declieuxia psychotrioides DC. are lectotypified.