Epidendrum (Orchidaceae) has been suggested to be a promising model system for evolutionary and ecological studies in the Neotropical region. Given its species diversity, the broad biogeographical and ecological range, and the variation in morphology, chromosome numbers and ecological interactions, the genus presents a rich source for intriguing and yet unanswered questions. Epidendrum is also a prime candidate to study speciation and this makes establishing precise species boundaries and diversity estimates in the genus extremely important. Through the recognition and discovery of hundreds of undescribed taxa, the number of formally described Epidendrum species has grown from 1000 to 1800 in the last two decades, while projections suggest the genus may have up to ca. 2400 species. This notorious underestimation of species diversity has serious consequences in many macroecological studies, including speciation, biogeographical patterns, diversification processes, and conservation priorities. Such a large number of unrecognized species in the genus has multiple unforeseen negative consequences and closing the gap between the described and projected diversity needs to become a priority. The isthmus of Costa Rica and Panama, one of the most biodiverse regions in the world, is also a center of diversity of Epidendrum. One out of every six species in the genus is present in the region and half of them are endemic. In the current paper, 20 new species are described from the isthmus and new records and exclusions are presented for both countries. Many of the newly recognized species had previously been included within broader circumscriptions of other taxa or had simply been misidentified. They represent a good example of how taxonomy can cause a sudden shift from a scenario where a few broadly distributed and unthreatened species become multiple potentially threatened species for which the population size, distribution and conservation status need to be urgently established. Epidendrum is the most specious orchid genus in Costa Rica and Panama, as well as most other Latin American countries, but species are poorly represented in herbaria and literature, and indetermination or incorrect determination of specimens is widespread. This results in a severe underestimation of Epidendrum species both in terms of species richness and their conservation priority levels.

Here we report two species as new for Mexico, G. arundinis and G. sobralioides, and discuss the report of G. batemanii for the state of Tabasco. A discussion of possible diagnostic characters of this genus and a key to the Mexican species also are presented.

Neea gustaviaefolia, a new species from the wet forests from “Sierra de La Macarena” and upper “Guaviare” river regions of Colombia (Guaviare and Meta departments) is described, illustrated, and its morphological relationships are discussed. This new species is a small tree of 6 m tall, on the basis of its alternate, oblanceolate larger leaves and a shorter terminal cymes inflorescence, verticillate (with three opposite primary branches), it does not appear to be closely allied to any other Neea species. This new species shares several other features with five species (N. alumnorum, N. brevipedunculata, N. floribunda, N. itanhaensis and N. verticillata). Morphologically, however, it is comparable to N. alumnorum and N. itanhaensis but it differs in its leaves, inflorescences, staminal perianth, and stamens number. In addition, ecological, floristic, and geological notes about the “La Sierra de La Macarena are included. A key for identifying species of Neea to Colombia is also provided. Neea gustaviaefolia is remarkable for its alternate, larges leaves (30–65 × 10–20 cm), in an otherwise predominantly opposite, small to medium (4–25 × 2–8 cm) leaved genus, and it increases to 27 the number of species of the genus to Colombia flora.

The type collection of Phoebe puwenensis consists of 18 specimens in the herbarium of Nanjing Forestry University (NF). Of those specimens, W. C. Cheng 30001 (NF2004054), which bears the notation “sp. nov.” and also a handwritten diagnosis, is chosen as the lectotype.

This work has as objectives to report five new records in Sida section Malacroideae (Malvaceae) for Caatinga vegetation from the Brazilian northeastern: Sida anomala, S. caulorrhiza, S. dureana, S. paradoxa, and S. simpsonii. Data on geographic distribution and reproductive phenology as well as comments on morphological characters for species recognition are provided.

The typification of the genus name Piaropus (Pontederiaceae) and the Validation of the sectional name “Toxicodendron sect. Venenata Gillis” are addressed.

After 113 years since the only Luvunga species was described from the Philippines and after 36 years since the latest species of the genus was formally described from Sabah, Borneo, a species new to science of Luvunga from Zamboanga del Norte, Southern Philippines, L. subanense, is described and illustrated. The new species differs from similar species, L. philippinensis and L. crassifolia, by having longer thorns, longer petioles and an inflorescence of four-flowered cymes. It further distinguishes from its most similar species, L. philippinensis, by having nine stamens (vs. 10), shorter filaments (4–4.5 mm vs. 6 mm) and ovoid ovary (vs. oblong) which is globular in cross-section (vs. quadrangular). Figures, a table of comparing the new species to L. philippinensis and L. crassifolia, notes on distribution, habitat and conservation status are provided. This novelty brings the total number of Luvunga species to 15 of which four are found in the Philippines.

The present study provides a taxonomic synopsis of Cordiaceae and Heliotropiaceae (Boraginales) for Uruguay. In order to gain full comprehension of the Uruguayan species in these groups, we examined collections at MVFA, MVJB and MVM, CTES, and SI, consulted virtual collections at F, K, NL-L, NL-U, and P, and studied the online collections hosted by the Herbário Virtual da Flora e dos Fungos-Reflora. We accept 19 species, six of which belong to Cordiaceae (Cordia and Varronia, each with three species) and 13 to Heliotropiaceae (Euploca with four species, Heliotropium with seven species, and Myriopus with two species). Euploca filiformis and E. krapovickasii are recorded for the first time for Uruguay. We provide identification keys for the recognition of each family and their species, a list of selected specimens, and comments on the morphology, distribution and phenology of each species.

Cirrhopetalum roseopunctatum is illustrated from the type specimen. It is found to be conspecific with the later Cirrhopetalum annamense. In Bulbophyllum the combined entities must be known as B. annamense due to the earlier B. roseopunctatum Schltr.

Cordia obtusiloba, a new species of Cordia section Gerascanthus (Cordiaceae), currently known to the hypoxerophytic caatinga of the state of Sergipe, Brazil, is described and illustrated. A distribution map, data on phenology, and conservation assessment are provided.

Ternstroemia killipiana, a species endemic to Cordillera Oriental of Colombia, was collected by Ellsworth P. Killip in 1926, and described by Clarence E. Kobuski in 1942. Since this date, this taxon it had not been recollected until the new collection reported here. A full description based on recent collection from “Serranía de Las Quinchas” (middle Magdalena river), Boyacá department, which for the first time includes detailed information on calyx and the corolla, an illustration, and an updated key to the 15 species of Ternstroemia reported from Colombia are provided. The presence of T. killipiana, and other endemic plant species, on both slopes of the Cordillera Oriental demonstrates the important role of intensive biological explorations in understudied areas, and also suggests that plant diversity on the middle Magdalena river slopes has not been thoroughly sampled.

Carpotroche caceresiae, a newly delimited species from the Caribbean drainage of Honduras and Nicaragua, is described and illustrated and its extinction threat assessed as Near Threatened (NT) according to IUCN criteria. Carpotroche caceresiae has previously been confused with C. platyptera, a species characterized by a densely pubescent lower leaf surface and red fruits lacking crests between the wings; in contrast, C. caceresiae has sparsely pubescent lower leaf surface and green fruits with crests between the wings. Carpotroche crassiramea and C. glaucescens, typified with Costa Rican material, and hitherto included in the synonymy of C. platyptera, are treated here as distinct morphological identities; a list of the specimens examined and referred to these names are provided.

Decaisnina samaense, a new species of Loranthaceae from the Island of Simunul, Southern Philippines, is hereby described and illustrated. It is distinguished from all Decaisnina species by having narrowly lanceolate and narrowly ovate-lanceolate leaf laminae with a remarkable acuminate apex, flower buds being globularly inflated at the base with corolla color being yellow in the lower half and pastel green in the upper half and often blackish at the tip, and inflorescence consistently produce both triads and peduncles along the axis. It is related to Decaisnina stenopetala and D. zollingeri by exhibiting globular inflation at the base of the flower buds but differs from the two by having longer bracts, longer anthers, and the free part of the filament shorter. Decaisnina samaense is hereby assessed as Critically Endangered (CR B1, B2a&c, D).

According to Article 9.2 of International Code of Nomenclature for algae, fungi, and plants (ICN, Shenzhen Code, 2018), the errors of collection number in the protologues of 14 names of Chinese plants were corrected, including Bauhinia bohniana (Fabaceae), Bauhinia dioscoreifolia (Fabaceae), Brassaiopsis glomerulata var. brevipedicellata (Araliaceae), Deutzia coriacea (Saxifragaceae), Fissistigma capitatum (Annonaceae), Gymnadenia monophylla (Orchidaceae), Hibiscus venustus var. integrilobus (Malvaceae), Hibiscus wangianus (Malvaceae), Hydrangea fulvescens (Hydrangeaceae), Ilex chuniana (Aquifoliaceae), Ilex corallina Franch. var. macrocarpa (Aquifoliaceae), Lonicera montigena (Caprifoliaceae), Morinda hupehensis (Rubiaceae), Neonauclea tsaiana (Rubiaceae). The holotypes of the 14 names are deposited in the Harvard University Herbaria.