ZOBODAT - www.zobodat.at Zoologisch-Botanische Datenbank/Zoological-Botanical Database Digitale Literatur/Digital Literature Zeitschrift/Journal: Annalen des Naturhistorischen Museums in Wien Jahr/Year: 2018 Band/Volume: 120B Autor(en)/Author(s): Berger Andreas Artikel/Article: Synopsis and typification of Mexican and Central American Palicourea (Rubiaceae: Palicoureeae), part I: The entomophilous species 59-140 ©Naturhistorisches Museum Wien, download unter www.zobodat.at Ann. Naturhist. Mus. Wien, B 120 59–140 Wien, Jänner 2018 Synopsis and typification of Mexican and Central American Palicourea (Rubiaceae: Palicoureeae), part I: The entomophilous species A. Berger* Abstract The prominent but complex genus Psychotria (Rubiaceae: Psychotrieae) is one of the largest genera of flow- ering plants and its generic circumscription has been controversial for a long time. Recent DNA-phyloge- netic studies in combination with a re-evaluation of morphological characters have led to a disintegration process that peaked in the segregation of hundreds of species into various genera within the new sister tribe Palicoureeae. These studies have also shown that species of Psychotria subg. Heteropsychotria are nested within Palicourea, which was traditionally separated by showing an ornithophilous (vs. entomophilous) pol- lination syndrome. In order to render the genera Palicourea and Psychotria monophyletic groups, all species of subg. Heteropsychotria have to be transferred to Palicourea and various authors and publications have provided some of the necessary combinations. In the course of ongoing research on biotic interactions and chemodiversity of the latter genus, the need for a comprehensive and modern compilation of species of Pali­ courea in its new circumscription became apparent. As first step towards such a synopsis, the entomophilous Mexican and Central American species (the traditional concept of Psychotria subg. Heteropsychotria) are covered here. These are enumerated and synonyms as well as an annotated list of type specimens are given. In addition, the new combination Palicourea croceovenosa (DWYER) A.C. BERGER is provided and a number of lectotypifications are made. Key words: Rubiaceae, Palicoureeae, Palicourea, Psychotria subg. Heteropsychotria, synopsis, typifica- tion, Mexico, Central America. Zusammenfassung Die taxonomisch schwierige Gattung Psychotria (Rubiaceae: Psychotrieae) ist eine der artenreichsten Pflan- zengruppen weltweit. Die Gattungsabgrenzung von Psychotria war lange ungeklärt. Erst aktuelle DNA-phy- logenetische und damit verbundene morphologische Untersuchungen konnten schließlich zeigen dass hun- derte Arten zu anderen Gattungen gehören, die zudem als eigener Tribus Palicoureeae von den Psychotrieae abzugrenzen sind. Zusätzlich erwies sich, dass Psychotria subg. Heteropsychotria zur Gattung Palicourea gehört, welche traditionell durch Vogelbestäubung (gegenüber Insektenbestäubung) unterschieden wurde. Damit Palicourea und Psychotria monophyletische Gruppen werden, müssen alle Arten von subg. Heterop­ sychotria zu Palicourea transferiert werden, was in vielen Einzelpublikationen der letzten Jahre teilweise durchgeführt wurde. Im Rahmen von aktuellen Untersuchungen über die Chemodiversität, Bestäubung und Herbivorie in dieser Pflanzengruppe zeigte sich, dass eine moderne Zusammenstellung aller Palicourea-Ar- ten von Nöten ist, welche bisher noch nicht vorlag. Als erster Schritt einer neuen Gattungssynopsis werden in der vorliegenden Arbeit alle mexikanischen und zentralamerikanischen Arten der Gattung Palicourea im erweiterten Sinn behandelt, welche Insektenbestäubung aufweisen und traditionell daher Psychotria subg. Heteropsychotria zugeordnet wurden. Diese Arten, deren Synonyme und ein kommentiertes Verzeichnis der Typusbelege werden präsentiert. Des Weiteren werden die neue Kombination Palicourea croceovenosa (DWYER) A.C. BERGER und eine Reihe von Lektotypisierungen vorgeschlagen. * Mag. Andreas Berger, Division of Systematic and Evolutionary Botany, Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria. – andi.berger@univie. ac.at. ©Naturhistorisches Museum Wien, download unter www.zobodat.at 60 Annalen des Naturhistorischen Museums in Wien, B, 120 Introduction Woody Rubiaceae are characteristic elements in any tropical and subtropical rainforest. One of the most prominent groups is the hyperdiverse and pantropical genus Psychotria L. It includes at least 1,600 species (RAZAFIMANDIMBISON & al. 2014) and ranks among the top 10 of the largest plant genera (FRODIN 2004). The neotropical genus Palicourea AUBL. has long been considered closely related and was traditionally separated by flow- ers showing characters associated with hummingbird rather than insect pollination. Its species are typically found in the understory of undisturbed rainforests and are frequent at high elevations where Psychotria and related genera are less speciose (TAYLOR 1996b, 1997). History of classification of Palicourea and Psychotria: Palicourea and Psychotria have long been classified in the tribe Psychotrieae. Recently, however, views shifted towards a narrower concept of Psychotria and Psychotrieae that peaked in the ongoing segre- gation of hundreds of species into a separate tribe, Palicoureeae (NEPOKROEFF & al. 1999, RAZAFIMANDIMBISON & al. 2014, ROBBRECHT & MANEN 2006). As one of the early workers, MÜLLER ARGOVIENSIS (1881) recognized that species classified in Psychotria comprise distinct groups, and that some are more closely related to Palicourea. He there- fore segregated the genus Mapouria AUBL., which cannot be retained since it is conge- neric with the type of Psychotria. Furthermore, he united Palicourea with the remaining species of Psychotria under the latter genus, which should have taken the name Pali­ courea. Using pyrene and seed characters, PETIT (1964, 1966) likewise recognized dis- tinct groups within African Psychotria. He restricted the genus to species possessing an alcohol-soluble red seed coat pigment and pyrenes lacking preformed germination slits. Although his studies were restricted to African species, the proposed circumscription of Psychotria already anticipated the segregation of many species to Palicourea. STEYERMARK (1972) again defined the genus Psychotria in a broader sense, but classi- fied Neotropical species into two subgenera. He based Psychotria subg. Psychotria on caducous stipules, a stipular scar with ferruginous hairs, dried leaves of reddish-brown, grayish to black color, and pyrenes usually with a plane ventral and a 4–5-ridged dorsal side. In contrast, he diagnosed subg. Heteropsychotria STEYERM. by persistent stipules, a lack of ferruginous hairs at the stipular scar, rather greenish drying color, and pyrenes with the ventral side usually 1-carinate or sulcate. Thus, Steyermark's subg. Psychotria corresponds to Mapouria as circumscribed by Müller Argoviensis and Psychotria as circumscribed by Petit. In contrast, subg. Heteropsychotria corresponds to Psychotria (sensu Müller Argoviensis) and Palicourea in its modern circumscription. Palicourea s.l.: Species of Palicourea and Psychotria subg. Heteropsychotria cannot be distinguished by vegetative or fruit characters (see, e.g., STEYERMARK 1972, TAYLOR 1996b). In addition, both show similar accumulation of alkaloids (BERGER & al. 2012, 2015, 2017), flavonoids (BERGER & al. 2016) and cyclotides (KOEHBACH & al. 2013). As traditionally defined, both deviate only in a suite of traits associated with pollination syndromes. In species of subg. Heteropsychotria, flowers are mostly arranged in open, somewhat grouped to densely capitate inflorescences with inconspicuously colored flo- ral and/or involucral bracts and inflorescence axes. Flowers are usually sessile or sub- sessile and have small, white, greenish or yellow corollas with short and straight tubes in bee-pollinated species or white and long-tubed corollas in moth-pollinated species. ©Naturhistorisches Museum Wien, download unter www.zobodat.at BERGER: Synopsis and typification of Mexican and Central American Palicourea 61 By contrast, species of Palicourea (s.trad.) are hummingbird-pollinated, frequently have long-pedunculate and open inflorescences, coloured inflorescence axes, large and long pedicellate flowers and vividly coloured corollas. These possess well-developed tubes with a gibbous, nectar accumulating swelling at their base, which is protected by an internal ring of hairs. In many plant groups, ornithophilous flowers have repeatedly evolved from entomophil- ous ancestors and are not phylogenetically informative at the generic level (e.g., CAS- TELLANOS & al. 2004, FENSTER & al. 2004, PIRIE & al. 2016). Hence, it was hypothesized that pollinator shifts have occurred multiple times in Palicourea and that humming- bird-pollinated species (i.e., the traditional concept of Palicourea) repeatedly evolved out of bee-pollinated ancestors (i.e., the traditional concept of Psychotria subg. Hetero­ psychotria) or vice versa (e.g., TAYLOR 1996, 1997). Starting with the work of ANDERSSON & ROVA (1999) and NEPOKROEFF & al. (1999), DNA sequence data indeed confirmed that Psychotria is paraphyletic and comprising of two major clades. One consists of Psychotria sensu Petit (Psychotria subg. Psycho­ tria sensu Steyermark), the myrmecophilous Hydnophytinae, and a few Pacific species traditionally referred to segregates of Psychotria. The other clade comprises of species mostly assigned to Palicourea and Psychotria subg. Heteropsychotria.