Psychotria Species Research Articles

Distyly and incompatibility in Psychotria homalosperma (Rubiaceae), an endemic plant of the oceanic Bonin (Ogasawara) Islands

Distyly rarely occurs on oceanic islands. Indeed, this form of polymorphism is absent on the Hawaiian Islands and in New Zealand. However, Psychotria homalosperma (Rubiaceae), which is endemic to the oceanic Bonin Islands of Japan, was presumed to maintain a distylous breeding system and floral morphology. We investigated the floral and reproductive characteristics of this species and examined incompatibility in self- and intramorph pollination. Psychotria homalosperma is morphologically and functionally distylous, based on findings with the examined populations, but its stigma and anther heights are not exactly reciprocal between the two morphs. This is the second example of distyly among the flora from the Bonin Islands, the other being the endemic P. boninensis. Both of these distylous species contrast with the Hawaiian Psychotria species, which have already become dioecious. The flowers of the long (L)-styled (pin) morph of the Bonin Islands plants are completely self- and intramorph incompatible, while the flowers of the short (S)-styled (thrum) morphs are partially intramorph compatible. The S-styled morph was more abundant in the examined populations from three islands of the archipelago, probably due to the existence of partial S–S intramorph compatibility.

Spatial genetic structure in four understory Psychotria species (Rubiaceae) and implications for tropical forest diversity.

• Premise of the study: Tropical forests are the most species-rich terrestrial communities on Earth, and understory trees and shrubs comprise a large fraction of their plant species diversity, especially at high rainfalls. The mechanisms responsible for generating such high levels of diversity remain unknown. One hypothesis is that fleshy-fruited understory species should have limited seed dispersal due to the sedentary nature of their avian dispersers, resulting in restricted gene flow, population differentiation at small spatial scales, and ultimately, high rates of allopatric speciation.• Methods: We sampled four species of the hyperdiverse tropical shrub genus Psychotria (Rubiaceae) on Barro Colorado Island (BCI) and two nearby sites in Panama. We genotyped each species with AFLPs, assessed genetic differentiation among populations, and determined patterns of fine-scale spatial genetic structure in the BCI population. Measures of spatial autocorrelation and population density were used to estimate the dispersal distance parameter σ.• Key results: Regionally, ΦPT values ranged from 0.13 to 0.28, reflecting local population differentiation and suggesting that Lake Gatun/Rio Chagres has posed a relatively strong barrier to gene flow. Fine-scale spatial genetic structure on BCI was stronger than in most canopy trees, and estimated distances of gene flow were unusually low for endozoochorous tropical woody plants, with dispersal distance σ = 9-113 m.• Conclusions: These results demonstrate comparatively limited gene flow in bird-dispersed understory species, supporting a hypothesized mechanism for generating high levels of plant species diversity in tropical rain forests, in one of the largest genera of flowering plants on Earth.

Four new species of Psychotria (Rubiaceae) from New Caledonia, including one presumed to be extinct

Psychotria (Rubiaceae) is the second largest genus of flowering plants in New Caledonia. A taxonomic revision in progress for this archipelago estimates the number of species as 81, all of them endemic, and 25 of which are new to science. Four of them are described and illustrated here: P. fambartiae, P. ireneae, P. nigotei and P. veillonii. Robust morphological characteristics were found to distinguish these four from other New Caledonian species. Psychotria veillonii, which is known only from the massif of Tiébaghi, might already be extinct as a result of intensive nickel mining in the area. According to the IUCN criteria, P. nigotei, should be considered Critically Endangered as it occurs only in two locations, which are close to one another; P. ireneae and P. fambartiae are considered Endangered and Vulnerable respectively, given their somewhat larger but limited distributions.

Proteomics Analysis of Psychotria Leaf Nodule Symbiosis: Improved Genome Annotation and Metabolic Predictions

Several plant species of the genus Psychotria (Rubiaceae) harbor Burkholderia sp. bacteria within specialized leaf nodules. The bacteria are transmitted vertically between plant generations and have not yet been cultured outside of their host. This symbiosis is considered to be obligatory because plants devoid of symbionts fail to develop into mature individuals. The genome of 'Candidatus Burkholderia kirkii' has been sequenced recently and has revealed evidence of reductive genome evolution, as shown by the proliferation of insertion sequences and the presence of numerous pseudogenes. We employed shotgun proteomics to investigate the expression of 'Ca. B. kirkii' proteins in the leaf nodule. Drawing from this dataset and refined comparative genomics analyses, we designed a new pseudogene prediction algorithm and improved the genome annotation. We also found conclusive evidence that nodule bacteria allocate vast resources to synthesis of secondary metabolites, possibly of the C7N aminocyclitol family. Expression of a putative 2-epi-5-valiolone synthase, a key enzyme of the C7N aminocyclitol synthesis, is high in the nodule population but downregulated in bacteria residing in the shoot apex, suggesting that production of secondary metabolites is particularly important in the leaf nodule.

Screening of Extracts of Leaves and Stems of Psychotria spp. (Rubiaceae) against Sitophilus zeamais (Coleoptera: Curculionidae) and Spodoptera frugiperda (Lepidoptera: Noctuidae) for Maize Protection

Sitophilus zeamais (Coleoptera: Curculionidae) and Spodoptera frugiperda (Lepidoptera: Noctuidae) are important economic pests of corn, Zea mays (Poaceae). Psychotria spp. (Rubiaceae) plants are rich in secondary metabolites that could be toxic against such pests. We have screened extracts from four species of Psychotria abundant in the Cerrado (Savannah-type) biome of Brazil for the toxicity to two insects. We found that extracts from leaves and stems had significant effects on the hatching rate, parameters of caterpillar body (weight and length and width of head capsule), repellency, and mortality of these two pests, although the effects varied according to the Psychotria species and plant source (stem or leaf). Extracts of the stems of Psychotria hoffmannseggiana and of Psychotria capitata were more toxic to S. zeamais and the stems of Psychotria goyazensis to S. frugiperda; therefore, such extracts could have the potential for use in integrated pest management schemes.

New and little-known Psychotria (Rubiaceae) from West Africa, and notes on litter-gathering angiosperms

Background - Five new species of Psychotria (Rubiaceae) from West Africa are described and illustrated, in the framework of a regional revision of the genus. Methods - Normal practices of herbarium taxonomy have been applied. Key results - Three of the new species, Psychotria baldwinii, P. tetragonopus and P. voorhoevei, are endemic to Liberia, while the other two, P. blydeniae and P. rubriceps, also occur in adjacent southwestern Cote d'Ivoire. The Ivorian endemic Psychotria copeensis, previously included in the synonymy of P. subobliqua, is separated as a distinct species. Psychotria blydeniae and P. tetragonopus are litterbin plants.we discuss this remarkable adaptation and its occurrence in various Angiosperm families in the African rainforests. © 2013 National Botanic Garden of Belgium and Royal Botanical Society of Belgium.

New records for the flora of Cameroon, including a new species of Psychotria (Rubiaceae) and range extensions for some rare species

Background - The inventory of Cameroon's flora is far from complete and additional work is needed to document the country's extremely rich flora, and thus enhance its conservation. In this framework, botanical exploration was conducted between 2007 and 2011 in various regions of Cameroon and resulted in the discovery of several new national records and new species. Methods - Normal practices of herbarium taxonomy have been applied. For the endemic or subendemic species, a preliminary IUCN conservation has been proposed using the IUCN criteria. Results - A total of twelve taxa are recorded as new for the flora of Cameroon. Significant range extensions are reported for eight restricted-range species. A new species, Psychotria yaoundensis O.Lachenaud, endemic to Cameroon and only know from two rocky hills in the surroundings of Yaounde, is described and illustrated. Additions to the flora of Equatorial Guinea (five species), Nigeria, Ivory Coast and the Democratic Republic of Congo (one species each) are also reported. Psychotria moliwensis and Vangueriopsis gossweileri are synonymised under P. fernandopoensis and V. rubiginosa, respectively. Conclusion-Many areas within Cameroon remain botanically poorly explored. Our exploration highlights the importance of the Rumpi Hills, Tchabal Mbabo, and the rocky hills around Yaounde for plant conservation. Our data will help conservationists in determining areas highly valuable for conservation. © 2013 National Botanic Garden of Belgium and Royal Botanical Society of Belgium.

Phenological synchrony and seasonality of understory Rubiaceae in the Atlantic Forest, Bahia, Brazil

In tropical forests with low seasonality, climatic variables generally exert a weak influence on the phenology of species. The seasonality of phenophases in closely related taxa can be controlled by phylogenetic constraints in such environments. In this study, our aim was to describe the phenology of Rubiaceae in the understory of the Atlantic Forest in the southern part of Bahia, Brazil, as well as to evaluate the seasonality and phenological synchrony of this family. For two years, we observed 90 individuals belonging to 13 species, in an area of 0.2 ha. Leaf flushing and leaf fall did not demonstrate any seasonality, were continuous for most species and correlated with few of the climatic variables. Flowering was seasonal and correlated positively with all climatic variables. Species exhibited seasonality for this phenophase with high flowering overlap among species of Psychotria, indicating an aggregated pattern for this genus. Fruiting was also seasonal and correlated with all the climatic variables, unripe fruit development peaking at the beginning of the season during which humidity is highest and fruit ripening peaking in the season during which humidity is slightly lower. The vegetative and flowering patterns observed in the study area are commonly seen in other tropical forests. The reproductive seasonality of this family can facilitate the attraction of biotic agents, as postulated in the facilitation hypothesis. Our results demonstrate that climatic variables influenced the phenological patterns observed here, although the high reproductive seasonality and interspecific synchrony, especially in congeneric species, raises the possibility that phylogenetic proximity plays a role in the pattern of the family Rubiaceae.

Post-treatment with plant extracts used in Brazilian folk medicine caused a partial reversal of the antiproliferative effect of glyphosate in the Allium cepa test

Species of the genus Psychotria are used for multiple purposes in Brazilian folk medicine, either as water infusions, baths or poultices. This study was aimed to evaluate the genotoxic and antiproliferative effects of infusions of Psychotria brachypoda and P. birotula on the Allium cepa test. Exposure to distilled water was used as a negative control, while exposure to glyphosate was used as a positive control. The interaction of extracts (as a post-treatment) with the effects of glyphosate was also studied. Results showed that glyphosate and the extracts of both P. brachypoda and P. birotula reduced the mitotic index as compared with the negative control (distilled water). Surprisingly, however, both extracts from P. brachypoda and P. birotula caused a partial reversal of the antiproliferative effect of glyphosate when used as a post-treatment. Glyphosate also induced the highest number of cells with chromosomal alterations, which was followed by that of P. birotula extracts. However, the extracts from P. brachypoda did not show any significant genotoxic effect. Post-treatment of glyphosate-treated samples with distilled water allowed a partial recovery of the genotoxic effect of glyphosate, and some of the Psychotria extracts also did so. Notably, post-treatment of glyphosate-treated samples with P. brachypoda extracts induced a statistically significant apoptotic effect. It is concluded that P. brachypoda extracts show antiproliferative effects and are not genotoxic, while extracts of P. birotula show a less potent antiproliferative effect and may induce chromosomal abnormalities. The finding of a partial reversion of the effects of glyphosate by a post-treatment with extracts from both plants should be followed up.

Delimitation of the genus Margaritopsis (Rubiaceae) in the Asian, Australasian and Pacific region, based on molecular phylogenetic inference and morphology

AbstractIn the past, the circumscription of the large genus Psychotria (Rubiaceae) was difficult, until molecular phylogenetic studies revealed its considerable paraphyly, enabling the delimitation of its major lineages and the grouping of related genera, and most notably the separation of Psychotria and its relatives (former Psychotrieae) into two tribes: Psychotrieae and Palicoureeae. The genus Margaritopsis, which is included in Palicoureeae, encompasses 27 Neotropical species, and in previous studies these have been shown to be close relatives of a group of eight Psychotria species that occur over a large region extending from South‐East Asia to tropical South Pacific through Malesia (= the AMP region, defined as including South‐East Asia, Malesia, tropical Australia, Melanesia, Micronesia, New Caledonia and Polynesia). A molecular phylogenetic study, using one nuclear DNA region (ITS) and four plastid DNA regions (ndhF, rps16, trnH‐psbA, trnT‐F), is undertaken in order to test the placement of 17 AMP Psychotria species within Palicoureeae. The phylogenetic results show that they form a monophyletic clade (= clade G), which also includes the monotypic Fijian genus Readea and Hodgkinsonia frutescens from Australia. Clade G is embedded in a well‐supported grade with five Neotropical representatives of Margaritopsis. A morphological survey based on twenty characters, with the potential to circumscribe generic entities, shows that the monophyly of clade G is supported by a character combination that is similar to species of Neotropical Margaritopsis, confirming their inclusion in this genus. Taxonomic and nomenclatural work on these species is required to formalize nomenclatural implications. Based on the same set of morphological characters, but in absence of molecular data, 28 other Psychotria species from the AMP region were detected as likely candidates for inclusion in Margaritopsis, allowing the estimation of species richness of clade G to be a minimum of 47 species. Within clade G, five well‐supported subclades and a Readea lineage are delimited and each of these is generally supported by unique morphological features. Phylogenetic topologies reveal biogeographical patterns, including a main route of dispersal from western to eastern parts of the AMP region, with subsequent dispersals between archipelagos in the region.

Un nouveau Psychotria (Rubiaceae) rhéophyte du sud Cameroun

Background - A new species of Psychotria (Rubiaceae) from Cameroon is described and illustrated, in the framework of a regional revision of the genus. Methods - Normal practices of herbarium taxonomy have been applied. Key results - Psychotria torrenticola O.Lachenaud & Sene is remarkable in its rheophytic habit, narrowly lanceolate leaves, and in having very large flowers for the genus. It is closely related to P. psychotrioides (DC.) Roberty, from which, in addition to flower size, it also differs in having smooth pyrenes and fewerflowered inflorescences. The species is only known from the Ntem river valley near Nyabessan. Since the construction of a dam is scheduled in the region, the species is considered as Critically Endangered (CR B1a,b(iii)) according to IUCN criteria. © 2012 National Botanic Garden of Belgium and Royal Botanical Society of Belgium.

Psychotria kosraensis(Rubiaceae), a New Species from Kosrae, Caroline Islands, Micronesia

Psychotria kosraensis Lorence & K. R. Wood (Rubiaceae, Rubioideae), a narrow endemic from Kosrae, Caroline Islands, Federated States of Micronesia (FSM), is described and illustrated. The new species differs from other known species of Psychotria L. in Micronesia by its combination of narrowly obovate-elliptic or narrowly elliptic leaves with long-acuminate apex and abaxially barbate leaf axils, pseudoaxillary fasciculate inflorescences with very short peduncles ca. 1 mm, flowers with a long calyx tube with narrowly triangular lobes, and villosulous fruits crowned with the persistent well-developed calyx tube and lobes. Known from a single population of five individuals, P. kosraensis easily falls into the IUCN Red List category of Critically Endangered (CR).

Trait evolution and the coexistence of a species swarm in the tropical forest understorey

Summary1. A small number of species‐rich plant genera make a substantial contribution to the α diversity of tropical forests. These ‘species swarms’ (Gentry 1982) challenge a view of community assembly that maintains that niche overlap, and hence, the likelihood of competitive exclusion should increase with phylogenetic affinity. Related species may, however, occupy different microhabitats within a forest stand or, alternatively, differ ecologically in ways that allow them to coexist syntopically.2. To explore the relationship between phylogenetic history and niche differentiation among sympatric, congeneric species, we performed phylogenetic analyses of microhabitat preferences, photosynthetic and hydraulic traits, and experimental responses to light and water availability for 20 species ofPsychotria(Rubiaceae) from Barro Colorado Island (BCI), Panama.3. ThePsychotriapresent in small (3‐m radius), circular plots were more closely related than expected by chance. Photosynthetic and hydraulic traits were both associated with species habitat distributions, but only hydraulic traits were conserved phylogenetically. Experimental responses to water availability were also conserved phylogenetically. Functional trait analyses revealed little or no evidence of niche partitioning within sites.4. We conclude thatPsychotriaspecies’ responses to both light and moisture availability determine their microhabitat distributions on BCI and that evolutionarily conserved hydraulic traits lead to phylogenetic clustering of co‐occurring species.5. Synthesis. The evolutionary conservation of hydraulic traits related to soil moisture tolerance largely explains phylogenetic clustering in the local assembly of the hyperdiverse genusPsychotria. We suggest that close relatives are unlikely to exclude one another from shared habitats because resource availability is determined largely by asymmetric competition with the overstorey, rather than by competition with neighbouring understorey plants. In light of the recent biogeographic admixture in central Panama, the phylogenetic niche conservatism exhibited byPsychotriaon BCI raises the possibility of an association between local microhabitats and the ancestral climatic regimes under which majorPsychotrialineages evolved before arriving in sympatry.

The eroded genome of a Psychotria leaf symbiont: hypotheses about lifestyle and interactions with its plant host

Several plant species of the genus Psychotria (Rubiaceae) harbour Burkholderia sp. bacteria within specialized leaf nodules. The bacteria are transmitted vertically between plant generations and have not yet been cultured outside of their host. This symbiosis is also generally described as obligatory because plants devoid of symbionts fail to develop into mature individuals. We sequenced for the first time the genome of the symbiont of Psychotria kirkii in order to shed some light on the nature of their symbiotic relationship. We found that the 4 Mb genome of Candidatus Burkholderia kirkii (B. kirkii) is small for a Burkholderia species and displays features consistent with ongoing genome erosion such as large proportions of pseudogenes and transposable elements. Reductive genome evolution affected a wide array of functional categories that may hinder the ability of the symbiont to be free-living. The genome does not encode functions commonly found in plant symbionts such as nitrogen fixation or plant hormone metabolism. Instead, a collection of genes for secondary metabolites' synthesis is located on the 140 kb plasmid of B. kirkii and suggests that leaf nodule symbiosis benefits the host by providing protection against herbivores or pathogens.

Screening for leaf-associated endophytes in the genus Psychotria (Rubiaceae)

Burkholderia endophytes were identified within the leaves of non-nodulated members of the genus Psychotria. In contrast to leaf-nodulated Psychotria species, which are known to accommodate their endosymbionts into specialized endosymbiont-housing structures, non-nodulated species lack bacterial leaf nodules and harbor endosymbionts intercellularly between mesophyll cells. Based on molecular data (rps16, trnG, and trnLF), the phylogenetic reconstruction of the host plants revealed a separate origin of leaf-nodulated and non-nodulated Psychotria species. Despite a distinct phylogenetic position of the two host clades, the endophytes of the non-nodulated plants were not placed into a single monophyletic group but were found to be closely related to the leaf-nodulated endosymbionts. The observation of genetically similar endophytes in both nodulated and non-nodulated Psychotria lineages suggests that the host plant is playing a crucial role in the induction of leaf nodule formation. Moreover, the concentration of endosymbionts into specialized leaf nodules may be considered as a more derived evolutionary adaptation of the host plant, serving as an interface structure to facilitate metabolic exchange between plant and endosymbiont.

Monoamine oxidase inhibition by monoterpene indole alkaloids and fractions obtained from Psychotria suterella and Psychotria laciniata

Alkaloid fractions of Psychotria suterella (SAE) and Psychotria laciniata (LAE) as well as two monoterpene indole alkaloids (MIAs) isolated from these fractions were evaluated against monoamine oxidases (MAO-A and -B) obtained from rat brain mitochondria. SAE and LAE were analysed by HPLC-PDA and UHPLC/HR-TOF-MS leading to the identification of the compounds 1, 2, 3 and 4, whose identity was confirmed by NMR analyses. Furthermore, SAE and LAE were submitted to the enzymatic assays, showing a strong activity against MAO-A, characterized by IC50 values of 1.37 ± 1.05 and 2.02 ± 1.08 μg/mL, respectively. Both extracts were also able to inhibit MAO-B, but in higher concentrations. In a next step, SAE and LAE were fractionated by RP-MPLC affording three and four major fractions, respectively. The RP-MPLC fractions were subsequently tested against MAO-A and -B. The RP-MPLC fractions SAE-F3 and LAE-F4 displayed a strong inhibition against MAO-A with IC50 values of 0.57 ± 1.12 and 1.05 ± 1.15 μg/mL, respectively. The MIAs 1 and 2 also inhibited MAO-A (IC50 of 50.04 ± 1.09 and 132.5 ± 1.33 μg/mL, respectively) and -B (IC50 of 306.6 ± 1.40 and 162.8 ± 1.26 μg/mL, respectively), but in higher concentrations when compared with the fractions. This is the first work describing the effects of MIAs found in neotropical species of Psychotria on MAO activity. The results suggest that species belonging to this genus could consist of an interesting source in the search for new MAO inhibitors.

Iridoids as chemical markers of false ipecac (Ronabea emetica), a previously confused medicinal plant

Ethnopharmacological relevanceSeveral roots or rhizomes of rubiaceous species are reportedly used as the emetic and antiamoebic drug ipecac. True ipecac (Carapichea ipecacuanha) is chemically well characterized, in contrast to striated or false ipecac derived from the rhizomes of Ronabea emetica (syn. Psychotria emetica). Besides its previous use as substitute of ipecac, the latter species is applied in traditional medicine of Panama and fruits of its relative Ronabea latifolia are reported as curare additives from Colombia. Materials and methodsCompounds of Ronabea emetica were isolated using standard chromatographic techniques, and structurally characterized by NMR spectroscopy and mass spectrometry. Organ specific distribution in Ronabea emetica as well as in Ronabea latifolia was further assessed by comparative HPLC analysis. ResultsFour iridoid-glucosides, asperuloside (1), 6α-hydroxygeniposide (2), deacetylasperulosidic acid (3) and asperulosidic acid (4) were extracted from leaves of Ronabea emetica. Rhizomes, used in traditional medicine, were dominated by 3. HPLC profiles of Ronabea latifolia were largely corresponding. These results contrast to the general tendency of producing emetine-type and indole alkaloids in species of Psychotria and closely related genera and merit chemotaxonomic significance, characterizing the newly delimited genus Ronabea. ConclusionsThe aim of the work was to resolve the historic problem of adulteration of ipecac by establishing the chemical profile of Ronabea emetica, the false ipecac, as one of its less known sources. The paper demonstrates that different sources of ipecac can be distinguished by their phytochemistry, thus contributing to identifying adulterations of true ipecac.

Introduction to Botany of the Marquesas Islands: new taxa and combinations papers

Introduction to Botany of the Marquesas Islands: new taxa and combinations papers

Dopamine-iridoid alkaloids in Carapichea affinis (= Psychotria borucana) confirm close relationship to the vomiting root Ipecac

Broad-based HPLC-UV comparison of 57 methanolic crude extracts of the Psychotria complex (Rubiaceae), representing about 20 different species collected in Costa Rica, exhibited a clear chemical segregation of Psychotria borucana . In contrast to the more widespread tryptamine-iridoid alkaloids it deviated by an accumulation of dopamine-iridoid alkaloids. Similar to the South American vomiting root Ipecac, Psychotria ipecacuanha (= Cephaelis ipecacuanha ), cephaeline and emetine were found together with four related glycosides characterized by various N -acylations. Two glycosides were identified as the known N -acetates ipecoside and 6- O -methylipecoside, whereas the two others represent corresponding N - O -methylcaffeate derivatives from which borucoside was described as a new compound. Structure elucidation of all compounds was carried out by NMR- and MS-analyses supported by CSEARCH-NMR-database system. In addition to morphological characters and analyses of nucleotide sequence variation the chemical profile of P. borucana supported a recent taxonomic rearrangement where it has been grouped together with P. ipecacuanha in a separate genus Carapichea . ► HPLC-UV comparison of 57 methanolic crude extracts of 20 different Psychotria species from Costa Rica showed a clear chemical segregation of P. borucana . ► Instead of the more widespread tryptamine-iridoid alkaloids P.borucana deviates by an accumulation of dopamine-iridoid alkaloids. ► Together with morphological characters and DNA sequence data phytochemical results confirm the taxonomic rearrangement of P. borucana in a separate genus Carapichea together with C. ipecacuanha . ► Apart from the known aglyca cephaeline and emetine four related glycosides were isolated and identified from which borucoside was described as a new compound.

Rubiacearum Americanarum Magna Hama Pars XXVIII: New Taxa, New Combinations, New Names, and Lectotypification for Several Species Found in Mexico and Central America

The Neotropical genus Borojoa Cuatrec. (Rubiaceae) is now considered a synonym of Alibertia A. Rich. ex DC. Consequently, three species named in Borojoa and found in Costa Rica and Panama are transferred to Alibertia with these corresponding nomenclatural changes: the new combination A. atlantica (Dwyer) Delprete & C. H. Perss. is based on B. atlantica Dwyer, the new name A. dwyeri Delprete & C. H. Perss. is provided for B. panamensis Dwyer, and the new combination A. patinoi (Cuatrec.) Delprete & C. H. Perss. is provided for B. patinoi Cuatrec. Additionally, the species A. premontana C. M. Taylor is reduced to a variety of A. edulis (Rich.) A. Rich. ex DC., as A. edulis var. premontana (C. M. Taylor) Delprete & C. H. Perss. A lectotype is selected for A. edulis. The recent publication of Arachnothryx chimalaparum Lorence ex Borhidi designated a holotype deposited at MO, but no such specimen has been located; a lectotype is here chosen based on a duplicate of the holotype deposited at MEXU. The new species Notopleura recondita Hammel & C. M. Taylor of the Osa Peninsula of Costa Rica can be distinguished from N. polyphlebia (Donn. Sm.) C. M. Taylor by its leaf blades with the secondary veins plane on the adaxial surface and its short cymose or paniculiform inflorescences. The new species Palicourea matamana C. M. Taylor of premontane forests of central-eastern Costa Rica can be separated from P. orosiana C. M. Taylor by its larger stipules, longer calyx lobes, and hirsute pubescence. The new species P. providenciana J. Sánchez-Gonz. & C. M. Taylor of montane forests in south-central Costa Rica can be separated from P. hammelii C. M. Taylor by its longer lanceolate stipule lobes, dark purple or yellow-flushed inflorescences, and shorter calyx lobes. The Panamanian plants treated previously as Psychotria acuminata subsp. boraginoides Dwyer are here considered to differ at the species level from P. acuminata Benth., and accordingly the new combination P. boraginoides (Dwyer) C. M. Taylor is here published for this species. Clarification of the identity of Cephaelis croatii Dwyer shows that it is a distinct species of Psychotria, and the new combination P. croatii (Dwyer) C. M. Taylor is published here for this species. The new species P. herrerana C. M. Taylor of central Costa Rica can be recognized by its combination of large, sessile, elliptic leaves, its large paniculiform inflorescences, and its relatively small corollas. Study of the Costa Rican plants previously called Rudgea thyrsiflora Donn. Sm. shows that these do not have the characters of Rudgea, but are similar to Psychotria racemosa Rich. and better included in this latter genus; the new name P. tsakiana C. M. Taylor is here published for this species. The new combination Simira panamensis (Dwyer) C. M. Taylor is published here based on the name Bathysa panamensis Dwyer, which has priority over the name S. darienensis Dwyer; both of the names Dwyer published are based on the same type specimen, thus the later name S. darienensis is illegitimate.