The following new combinations Ceratocnemum aphanoneurum, C. ballii, Eutrema angustifolium, E. sulphureum, E. watsonii, Rhamphospermum labasii, R. nigrum, and R. pubescens are proposed. As a result Rhamphospermum is resurrected, Trachystoma is reduced to synonymy of Ceratocnemum, and Sinapis becomes dispecific.

Maytenus species bearing fruits with a coriaceous pericarp that open by two valves and having seeds that are completely covered by a white aril are currently placed in the genus Monteverdia. One hundred and twenty-three combinations have been proposed following these two diagnostic characters. However, according to Art. 41.5 of the International Code of Nomenclature for algae, fungi and plants, one of these combinations has not been validly published. The validation of the combination Monteverdia psammophila is provided here through the presentation of the complete citation of its basionym.

Barra Honda National Park (BHNP) lies in the Tempisque River Basin of the Península de Nicoya, Guanacaste, Costa Rica. The Park is well known for its limestone caverns, which date from the Upper Paleocene–Lower Eocene and are the main attraction of BHNP. The area shows a marked climatic seasonality with a predominantly semideciduous tropical dry forest. We present a floristic treatment of the orchids of BHNP based on field collections, herbarium sampling, and documentation of living specimens. We discuss the biodiversity, climate, geology, and topography of the Park and provide a novel vegetation zones map with eight floristic associations: bean plantations, disturbed secondary forest, evergreen forest, jaragua fields, mature secondary forests, pastures, rocky areas, karstic limestone pavement, and young secondary forest. For the 36 species belonging to 29 genera recorded, we provide composite line drawings and Lankester composite digital plates, descriptions, distribution, ecology, etymology, synonymy, taxonomy, photographs, and a key to the species for field identification based on morphology. Ten species of orchids (27.8%) are terrestrials and 26 are epiphytes (72.2%). The evergreen forest contains 80% of the orchid species of BHNP. We describe Pelexia barrahondaensis and Sarcoglottis calcicola as new to science, and we propose a new combination under Specklinia for Pleurothallis panamensis. Also, we record the terrestrial orchid genus Tropidia for the first time in Costa Rica. The present study provides new information on the Nicoya Peninsula's dry forest ecosystems for in situ conservation and research. This work can be useful for other protected areas within the same ecosystem that lack a floristic treatment of the Orchidaceae.

The genus Capparidastrum (Capparaceae) is discussed and C. estrellae, a new tree species endemic to northwestern Ecuador, is described and illustrated. Its conservation status is here assessed as endangered.

A new species of Sida section Malacroideae (Malvaceae), Sida nordestinensis, is described and illustrated. The new taxon is currently restricted to the State of Paraíba, Northeastern Brazil. This novelty is based on fieldwork and on the examination of relevant material from several herbaria. This study includes a taxonomic description, a distribution map, reproductive phenology data, and images for this new species.

This paper presents the distribution of Polycarpaea corymbosa in Brazil with particular attention to the state of Maranhão. Polycarpaea corymbosa is an herb with lanceolate leaves and capsular fruits. This paper provides data on area of distribution and taxonomy of the species.

Following Article 9.2 of the International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code, 2018), errors in the dates in the protologues of the names of eighteen taxa from China were corrected. They include Aralia plumosa (Araliaceae), Berberis bergmaniae var. acanthophylla (Berberidaceae), Biondia parviurnula (Asclepiadoideae, Apocynaceae), Boottia heterophylla (Hydrocharitacea), Bredia hainanensis (Melastomataceae), Cornus yunnanensis (Cornaceae), Cotoneaster glabrata (Rosaceae), Dendropanax productus (Araliaceae), Dendropanax stellatus (Araliaceae), Hedyotis obliquinervis (Rubiaceae), Hypericum macrosepalum (Clusiaceae), Lonicera flavipes (Caprifoliaceae), Pandanus gressittii (Pandanaceae), Pedicularis membranacea (Scrophulariaceae), Phyllagathis setotheca (Melastomataceae), Phyllagathis xanthotricha (Melastomataceae), Plagiopetalum quadrangulum (Melastomataceae), and Tylophora nana (Asclepiadoideae, Apocynaceae). The holotypes of all eighteen names are at the Harvard University Herbaria.

Vochysia carol-scottii from the pluvial forests of “Chocó biogeográfico,” a megadiverse region between the Pacific Ocean and the slopes of the Colombian Western Cordillera, Valle del Cauca department, is described and illustrated, and its morphological relationships with other similar Vochysia species are discussed. This new species is a small tree of 12 m tall and shares features with five species (V. artantha, V. assua, V. calamana, V. cayennensis, and V. tomentosa) of section Ciliantha. Morphologically, it is closest to V. artantha, but it differs in its leaves, inflorescences, spurred sepal, petals, and stamen size. A key and synopsis of the 44 species of Vochysia found in Colombia is provided. A brief note on the ethnobotany of Vochysia in the Amazon basin is presented in an appendix.

In this work a taxonomic revision is made of the nomenclature, distribution, and conservation status for the 84 species in the Colombian clade of Espeletia. Taxonomic changes include five new combinations for taxa at the species level that are transferred to Espeletia. Seventy-three species are endemic to the Colombian Cordillera Oriental (including four extending into the Venezuelan side of Páramo de Tamá), six are found in the Colombian Cordillera Central (four endemic to this range, one extending into Ecuador, and one shared with the Colombian Cordillera Occidental), three are endemic to the Colombian Cordillera Occidental, and two are endemic to Sierra de Perijá (including one yet to be found within Colombian borders). Geographic distributions at the páramo massif level are given for all species and subspecies. The IUCN Red List category is listed for each species, with suggestions for recategorization of some species with small distribution areas, low number of populations, and threats to their habitat extent and quality. In all, about 60 species in the Colombian Espeletia clade must be classified within a threatened category. When species belonging to the Venezuelan Espeletia clade that are found within Colombian borders are included, the current estimate of total diversity of Espeletia in this country is 90 species.

With the aim of recognizing and identifying both fertile and sterile specimens of Cryptocarya from Brazil, we analyzed the leaf venation pattern of 14 taxa, 6 of them being described and illustrated for the first time. A dichotomous identification key was built from a matrix of 12 leaf venation characters and 30 character states, which distinguishes among taxa.

Three new species of Lepanthes from the Western Cordillera of the Colombian Andes are described and illustrated. The new species were found during several botanical expeditions to the mountains in San José del Salado, department of Valle del Cauca, Colombia.

Four new arctic species of Draba are described here. Of these, D. airdii, D. shehbazii, and D. darbyshireii are from Canada, and D. catlingii is from both Canada and Alaska. Two new species described by others, D. adamsii and D. macrocarpa, are also added. The chromosome numbers n = 19 and 2n = 36 should be attributed to D. grandis, and n = 8 for D. lonchocarpa var. kamtschatica to D. chamissonis. Draba kluanei is now known to occur at a second location in Yukon. The six new Draba species added in this study bring the total number in Canada and Alaska to 65. A key to all of these species is presented.

Eleven new combinations are proposed in the recently established genus Blepharoglossum. Further, six names are found to be synonyms of earlier taxa in other genera and are here reduced to synonymy. Five names are also lectotypified, namely Dendrobium hastilabium, Eria dura, E. gracilicaulis, Habenaria zollingeri, and Trichotosia microbambusa.

We discuss a group of Pleurothallis species mostly characterized by plants relatively tall for the genus, with stems more than 20 cm long and fasciculate inflorescences produced above the leaf from a spathaceous, sometimes erect bract. We recognize 26 species and 4 natural hybrids in Costa Rica in this group of Pleurothallis, belonging to 4 informal assemblages of species, each one characterized by a unique set of vegetative, floral, and ecological features. This group, as well as its component units, is discussed as to its salient characteristics and internal relationships, underlying possible evolutionary trends. Diversity, general and floral ecology, color dimorphism, and natural hybridization are examined to address their systematic significance. We present a dichotomic key to the groups and the species discussed in this study, together with descriptions based on Costa Rican materials, and one or more line drawings or a Lankester Composite Dissection Plate when required for improved clarity. Also, we discuss their taxonomy and provide information on etymology, habitat, distribution, distinguishing features, and Costa Rican collections. Three species (P. callosa, P. longipetala, and P. mesopotamica), and three nothospecies (P. ×karremansiana, P. ×subversa, and P. ×parentis-certa) are described as new to science, discussed as to their affinities, and illustrated with photographs, composite digital plates, and ink drawings. Pleurothallis triangulabia is removed from the synonymy of P. phyllocardia, treated as a distinct species, and lectotypified. Pleurothallis anthurioides and P. maduroi are first recorded and documented for the flora of Costa Rica.