Rubiacearum Americanarum Magna Hama Pars XXV: The Nocturnally Flowering Psychotria domingensis–Coussarea hondensis Group Plus Three Other Mesoamerican Psychotria Species Transfer to Palicourea

Abstract

Several Neotropical shrubs and trees variously classified in Psychotria L. subg. Heteropsychotria Steyerm., Palicourea Aubl., and Coussarea Aubl. (Rubiaceae) share persistent stipules, apparently nocturnal flowers, well-developed white corollas with long tubes, and well-developed drupaceous fruits with two plano-convex pyrenes that generally have rather thin walls and are dorsally smooth or angled; additionally, most of these species have reduced stipules and relatively large fruits. The separation of Psychotria and Coussarea has been problematic at least in Central America, but removal here of six species from Coussarea leaves that genus characterized morphologically by 4-merous flowers and fruits with a single seed. Recent morphological and molecular surveys indicate that Palicourea and most species of Psychotria subg. Heteropsychotria comprise a single evolutionary group. These nocturnally flowering species all have the morphological features of Palicourea in this expanded circumscription and are here transferred to Palicourea along with three additional species from Mexico and Guatemala with relatively large, apparently hummingbird-pollinated flowers. Corresponding new combinations and names are published for several of these: Palicourea alajuelensis C. M. Taylor is based on Coussarea austin-smithii Standl.; Palicourea beachiana C. M. Taylor is based on Coussarea nigrescens C. M. Taylor & Hammel; Palicourea breedlovei (Lorence) Lorence is based on Psychotria breedlovei Lorence; Palicourea calidicola (C. M. Taylor) C. M. Taylor is based on Psychotria calidicola C. M. Taylor; Palicourea chrysocalymma (L. O. Williams) C. M. Taylor is based on Psychotria chrysocalymma L. O. Williams; Palicourea diguana (Standl. ex Steyerm.) C. M. Taylor is based on Cephaelis diguana Standl. ex Steyerm.; Palicourea eurycarpa (Standl.) C. M. Taylor is based on Psychotria eurycarpa Standl.; Palicourea faxlucens (Lorence & Dwyer) Lorence is based on Psychotria faxlucens Lorence & Dwyer; Palicourea grandifructa (C. M. Taylor) C. M. Taylor is based on Coussarea grandifructa C. M. Taylor; Palicourea heydei (Standl.) Lorence is based on Psychotria heydei Standl.; Palicourea hondensis (Standl.) C. M. Taylor is based on Psychotria hondensis Standl.; Palicourea mediocris (Standl. & Steyerm.) Lorence is based on Coussarea mediocris Standl. & Steyerm.; Palicourea megalantha (Lorence) Lorence is based on Psychotria megalantha Lorence; Palicourea nebulosa (Dwyer) C. M. Taylor is based on Coussarea nebulosa Dwyer; Palicourea neopurpusii C. M. Taylor is based on Psychotria purpusii Standl.; Palicourea psychotrioides (C. M. Taylor & Hammel) C. M. Taylor is based on Coussarea psychotrioides C. M. Taylor & Hammel; Palicourea roseocremea (Dwyer) C. M. Taylor is based on Coussarea roseocremea Dwyer; Palicourea sousae (Lorence & Dwyer) Lorence is based on Psychotria sousae Lorence & Dwyer; Palicourea tetragona (Donn. Sm.) C. M. Taylor & Lorence is based on Cephaelis tetragona Donn. Sm.; Palicourea thornei (Lorence) Lorence is based on Psychotria thornei Lorence; Palicourea tutensis (Dwyer) C. M. Taylor is based on Psychotria tutensis Dwyer; and Palicourea umbelliformis (Dwyer & M. V. Hayden) C. M. Taylor is based on Psychotria umbelliformis Dwyer & M. V. Hayden. The new species Palicourea pereziana C. M. Taylor is similar to these other nocturnally flowering species, and separated from Palicourea roseocremea by its smaller flowers and distribution in southern Costa Rica. Neotypes are designated for Palicourea domingensis (Jacq.) DC. (Psychotria domingensis Jacq.) and Palicourea gardenioides (Scheidw.) Hemsl. (Rhodostoma gardenioides Scheidw.).