A new species of Acianthera, A. lueri, is described and illustrated based on material collected in the Amazon region of Peru. The combination of the glabrous ovary, 3-lobed lip, and long-tailed petals distinguish A. lueri from similar A. lanceana. The new taxon is placed within the key to identification of species reported from the Peruvian Amazon region.

The identity of Epidendrum sclerocladium, currently referable to Encyclia, is clarified with the recent collection of material unambiguously referable to this entity. In addition, we provide a new name in Encyclia for this taxon, E. rhizomatosa Tamayo-Cen, Carnevali & G.A.Romero, because the current combination, E. sclerocladia (Lindl. ex Rchb.f.) Hoehne, is based upon the later homonym Epidendrum sclerocladium Lindl. ex Rchb.f. This name is predated by Epidendrum sclerocladium Lindley as we argue that Lindley validly published the name in a horticultural catalogue, a nomenclatural issue herein discussed. Furthermore, because the vegetative portions of the plants were unknown until recently, we provide an epitype to supplement the holotype for the unequivocal identification of the species. A preliminary assessment of its conservation status and phylogenetic relationships are presented. Encyclia thrombodes is discussed and it is concluded that no known plants are referable to this entity at this time. A lectotype is proposed for Epidendrum cyperifolium because the holotype was destroyed. Finally, we provide an annotated checklist of the Encyclia species known to occur in Peru.

A synoptic revision of the genus Epistephium in Colombia based on morphological evidence is presented for the first time. A total of 19 species gathered in 3 morphological groups are currently recognized in the country, including two new records: E. ellipticum and E. sclerophyllum. Morphological characteristics of all the species are presented and illustrated by line drawings of their perianth segments, except E. lamprophyllum. An original key to the identification of Epistephium species reported in Colombia is provided along with information on their ecology, habitat, and geographical range. Epistephium amplexicaule is lectotypified based on Article 9.3 of the International Code of Nomenclature for algae, fungi, and plants as this name was published without a holotype.

A new species of Dyckia (Bromeliaceae, Pitcairnioideae) from Maranhão, Northeastern Brazil is described and illustrated. Dyckia maranhensis is endemic in the cerrado phytogeographic domain and it was erroneously identified as D. braunii Rauh in herbarium collections. Information on its phenology, distribution, and conservation status is provided. The species is morphologically compared to D. dissitiflora Schult. & Schult. f., which is the most similar species.

The family Bromeliaceae is essentially Neotropical, with high endemism and diversity in the Atlantic Rainforest Domain. Species circumscription is a major problem in the family systematics, especially in the most diverse genera. Species of the Vriesea procera complex, which occur in forests and restinga (coastal vegetation) along the South American Atlantic coast from Venezuela to southern Brazil, share the same basic vegetative and reproductive morphological patterns. However, they vary widely in the number and position of inflorescence branches as well as in the dimensions, position, and shape of the leaves and flowers in different populations. Here we aimed 1) to evaluate the morphological variation in the V. procera complex, through morphometric analyses of natural populations along the Brazilian Atlantic Rainforest; and 2) to determine the taxonomic relationships among these species, establishing the validity and the limits of variation of the taxa through taxonomic treatment. Fourteen natural populations, 271 individuals, and 36 morphometric variables were analyzed. Kruskal-Wallis tests and discriminant analyses were conducted to test statistical differences between previously established groups. Of an original three species and three varieties, our data allowed us to recognize six species, including three new taxa (Vriesea aureoramosa, V. magna, V. rubroviridis) and one new name and status (V. flexuosa). The resulting taxa are distinguished by the inflorescence and leaf sizes and especially by floral characteristics such as the length of bracts, sepals, petals, stamens, and pistils, besides the petal apex posture and relative position of the stamen during anthesis. Recognition of cryptic species under the names V. procera and V. neoglutinosa is an important step toward a better understanding of the biodiversity of the Brazilian Atlantic Rainforest.

Merostachys delicatula, a new species recorded thus far only from the montane Atlantic forest of southern Bahia, is described and illustrated here. Comments on its taxonomy, distribution, habitat, and phenology are presented. Among the narrow-leaved congeners occurring in Bahia, the new species is most similar to M. leptophylla. It is distinguished by having internodes glabrous to scabrous (vs. glabrous in M. leptophylla); internodes with an infranodal band of trichomes (vs. absent); culm leaf sheaths abaxially scabrous (vs. glabrous); upper glumes 1.2–2.1 mm wide (vs. 3.5–4 mm); anthecia dull (vs. shiny); lemmas 1.5–2.7 mm wide, abaxially pubescent (vs. ca. 4 mm, glabrous); and paleas 1.2–2.3 mm wide (vs. ca. 4 mm). We also provide an assessment of the conservation status of the new species and a geographic distribution map for both species.

Two new diploid species, Aira minoricensis and Aira hercynica, are described and illustrated, along with chromosome counts, risk assessment, distribution and habitat, phenology, and comparisons with morphologically similar species. A comparative table and a key for the species of Aira for the Iberian Peninsula and the Balearic Islands are provided to assist in the identification of these overlooked species, and their relationships to other taxa are discussed.

A new species, Hymenaea jeaniana, is described and illustrated. The species is known from one of the best-sampled reserves of Amazon Rainforest, the Reserva Adolpho Ducke, in Manaus, and from protected areas of the municipality of Presidente Figueiredo, in Amazonas, Brazil. Previously, the species has been mistakenly assigned to the circumscription of the morphologically similar H. parvifolia, but differs in certain leaflet, inflorescence, and flower characteristics. The new species has a restricted distribution and is assessed as Endangered following IUCN Red List criteria. Based on herbarium collections and field studies, we present a full species description, an illustration, conservation status, and taxonomic comments. An identification key to the Hymenaea species of Brazil is also provided. There are six species of Hymenaea in the Amazon Basin, including the species described herein.

Ficus sirensis is described from Ucayali, northern Peru, and a new country record for F. macrosyce Pittier is given. Diagnostic features of both species are illustrated and a taxonomic key of Ficus sect. Pharmacosycea subsect. Petenenses from Peru is presented.

Two new species of Erythroxylum endemic to the Espinhaço Range, in eastern Brazil, are described. Erythroxylum itan occurs in seasonal forest on hilltops in the Itacambiruçu River valley, in the Grão Mogol region of northern Minas Gerais, and E. kanga occurs in campo rupestre and cerrado vegetation along the Espinhaço Range, in the states of Bahia and Minas Gerais. The new species are compared with morphologically similar species and illustrations and comments about distribution and habitat are provided. In addition, we present an updated list of Erythroxylum species from the Espinhaço Range.

Six new Kielmeyera species (Calophyllaceae) are presented here (K. cataractae, K. colibri, K. doceana, K. inopinata, K. oreophila, and K. stevensii), all from the Atlantic Forest in southeastern Brazil, from the states of Espírito Santo, Minas Gerais, and Rio de Janeiro. Complete descriptions, illustrations, and morphological comparisons with the most similar species for each new species are provided. We also estimated their conservation status according to IUCN criteria. Additionally, an identification key for Kielmeyera species with pollen grains in monads and usually ciliated sepal margins from Atlantic Forest and a comparison table are provided.

Three remarkable new species of Acalypha (Euphorbiaceae, Acalyphoideae) from Madagascar are described and illustrated. Acalypha isaloensis, found in the Isalo Massif of southwestern Ihorombe region, is morphologically similar to A. gracilipes, but differs by its habit, indument, presence of domatia, and inflorescence sexuality. This is the first report of pocket-shaped domatia in the genus. Acalypha rabesahalana and A. tremula, found in Diana and Sava regions in the far north of Madagascar, superficially resemble A. menavody, but they do not strongly resemble any other species known from Madagascar nor from mainland Africa. Preliminary conservation assessments of the three new species are provided, and all are considered endangered or critically endangered, despite occurring in legally protected areas.

A new species, Euphorbia adenoplicata, is here described and illustrated. The species was found in the vicinity of Serra Geral do Tocantins, close to the border of the states of Tocantins and Bahia, within the Cerrado biome, where it grows in cerrado rupestre (rocky savannah vegetation). Euphorbia adenoplicata is placed in Euphorbia sect. Crossadenia based on morphological characters. The species is unique within the section due to its cyathial glands with the margins folded in the middle portion, splitting each gland into two cavities. We compare the morphology and ecology of E. adenoplicata with E. sarcodes and other species of E. sect. Crossadenia subsect. Ephedropeplus. Finally, we recommend that E. adenoplicata be considered critically endangered due to its extreme rarity.

Psidium involutisepalum, a new species of Myrtaceae, is described and illustrated. The species is easily recognized by the combination of floral buds with calyx minute, truncate or rounded, 0.2–0.5 × 0.5–1 mm, involute in fruit, facing the receptacle. The fruits are rounded to pyriform, 20–30 × 13–20 mm, yellow when mature, glabrous, striate, sepals involute, facing the receptacle, seeds 1–6, 7–9 × 6–7 mm, rounded to angular. Based on the types and specimens examined, literature survey and the rules of international code of nomenclature, Psidium turbinatum is recognized here as a legitimate name. The relationship of Psidium involutisepalum, P. myrtoides, and P. turbinatum is discussed and comments concerning their taxonomy and ecology are also provided.

Microlicieae is a Neotropical tribe of Melastomataceae, and most of its species are endemic to Brazil, especially in campo rupestre sites. The campo rupestre ecosystem occurs in areas with shallow soils deficient in water and nutrients, and elevations above 900 m. Foliar characters provide important structural features which are of taxonomic value for Melastomataceae. Due to the high degree of endemism, taxonomic issues, and variety of water economy strategies found in Melastomataceae, our objective was to evaluate the leaf structure in 25 species of Microlicieae, aiming to identify potentially taxonomically informative characters which may have favored the radiation and diversification of this tribe. According to our results, Lavoisiera seems to be homogeneous regarding leaf characters, while Microlicia and Trembleya are highly variable in leaf size and general structure of veins and mesophyll. The leaf xeromorphism was presumably a relevant factor in the diversification of this tribe. Rhynchantera exhibited mesomorphic leaf characters, suggesting that the emergence of these features occurred after the divergence of this group from the rest of the clade.

The new species Alectryon hirsutus is described from New Caledonia. It is distinguished from the only other member of the genus occurring on this southwest Pacific island, A. carinatus, by its uniformly densely hirsute indumentum (vs. glabrous or with short, appressed trichomes) as well as features of its leaves [(2–)3–5 pairs of leaflets vs. 1–2]) and fruits (9–16 × 16–28 mm vs. 5.6–13 × 5.7–10.6 mm), along with its presence in dense humid forest (vs. sclerophyllous or lowland dry forest). A preliminary conservation status of Critically Endangered [CR] is suggested following IUCN Red List Categories and Criteria.

Acer iranicum (Sapindaceae s. l., Aceroideae), from the upper limits of the lowland forests toward the midlands in the western part of the Hyrcanian forests, is described as new. Diagnostic characters for A. iranicum are sub-leathery to papery leaves, rounded, elongate sepals, oblong-ovate petals, and samara wings diverging at 55–75°. The phylogenetic position of A. iranicum within Acer section Acer is elucidated based on analysis of the ITS data from representatives of all taxa within section Acer and morphological evidence. Acer iranicum was resolved as sister to A. opalus (Italian maple), but quite distant from all other species of maples in Iran.

To prepare for a revision of Guapira Aubl. in Brazil, this work proposes nomenclatural changes, typifications, and synonyms. We report twelve more species for the Brazilian flora, including the description of a new species, Guapira candanga, and resurrection of eleven names previously in synonymy. We rearrange the synonymy of some names, combine seven Pisonia species under Guapira, as G. apolinarii, G. cuneifolia, G. darwinii, G. florida, G. heterophylla, G. laurifolia, and G. platystemon, and designate lectotypes for four names.

Mandevilla athenastigma, endemic to inselbergs around Milagres in Bahia, Brazil is described. It resembles M. sancta (Stadelm.) Woodson, but is distinguished by its smaller corolla tube, larger anthers, and puberulent seeds. An illustration, color plates, a distribution map for the new species are included, and a key to the species of Mandevilla growing on inselbergs in northeastern Brazil is provided. A brief overview of the diversity of Mandevilla is given.

Molecular and morphological evidence supports a new species in the genus Antiphytum from the Sierra Madre del Sur, in the state of Guerrero, Mexico, here described as Antiphytum brevicalyx. This species is unique in the genus by possessing a calyx shorter than the corolla tube at anthesis; it is similar to A. floribundum in inflorescence arrangement, but differs from that species in lacking a basal leaf rosette and having appendages on the corolla throat. According to phylogenetic analysis of nuclear ITS and plastid ndhF-rpl32 sequences representing seven of the eight North American species of the genus besides the proposed new species, accessions of A. brevicalyx form a well-defined clade within Antiphytum, corroborating its distinctive morphology. However, the analyses do not resolve the phylogenetic position of A. brevicalyx within the genus.

Acanthaceae represent one of the most ecologically dominant families of plants in the Namib Desert and adjacent portions of Namibia and Angola yet have never been comprehensively treated from a taxonomic perspective in the region. Recent fieldwork in Angola yielded discovery of two populations of plants, morphologically allied to the tribe Ruellieae, that could not be ascribed to any known genus. Morphological study combined with molecular phylogenetic analysis based on ddRAD sequencing that sampled broadly across other lineages of Ruellieae yielded evidence for a new, previously undocumented lineage of Acanthaceae, which we here formally describe under the monotypic Mcdadea. Plants of M. angolensis are characterized as compact, weak-wooded shrubs with dense vegetation, minute corollas, and small, 2-seeded capsules. The species is restricted to limestone mesas and outcroppings in ultra-arid deserts of Namibe Province, southwestern Angola, where plants rely primarily on coastal fog for precipitation. Although highly range-restricted, there are no known threats to this species and it is currently assessed as of Least Concern. Molecular phylogenetic analyses suggest treatment of Mcdadea angolensis within a newly described subtribe of Ruellieae: Mcdadeinae. Additional revisions to subtribal classification are herein presented, including placement of Calacanthus within Ruelliineae, placement of Echinacanthus within Petalidiinae, and description of two additional new subtribes, Dinteracanthinae and Phaulopsinae.

Invasive species must colonize new habitats away from their native range; therefore, factors affecting plant dispersal play a key role in invasion. The ploidy level and genome size (or Cx value) can affect the dispersal traits, physiology, and ecology of invasive species over a few generations, generating individuals that can face fluctuating environments, exploit new ones, and compete with native species. Several studies have demonstrated that invasive species tend to have smaller genomes than their noninvasive congeners, which is explained by the role that the Cx value plays in phenotypic evolution and ecological tolerance. In order to test this hypothesis, we compare the genome size variation in Argentine populations (invasive range) vs. South African populations (native range) of S. madagascariensis. To meet our goals, we estimated the Cx value of invasive populations collected on field trips, while for native populations we considered available published data. We extracted the bioclimatic variables in order to establish the ecological amplitude in which the genome sizes may be distributed. Our results evidenced larger genomes in the invasive range than in the native one. Furthermore, we propose that large genomes of the invasive populations could be mainly explained by the founder genotypes effect and the anthropogenic introduction of this species to Argentina. In addition, we demonstrated that genotypes with big genomes can tolerate different environmental conditions from those of their native range. Therefore, they could present a greater ability for colonizing new environments. The implications and importance of ploidy level in the invasion of S. madagascariensis are discussed.

Valeriana caparaoensis, a new species from the High Altitude Tropical Grasslands of Southeastern Brazil, is described and illustrated. The new species is known only from the Serra do Caparaó massif, between the states of Minas Gerais and Espírito Santo, Southeastern Brazil. It shares morphological affinities with V. catharinensis and V. polystachya, the first restricted to Brazilian Subtropical Highland Grasslands, and the last restricted to Lowland Grasslands of Southern Brazil, Uruguay and Argentina. Besides the great geographical disjunction, the new species differs from the other two species by the pinnately lobed proximal leaves, by the lanceolate distal lobes and longer pseudopetioles in distal leaves, by differences in the size of the flowers, and by the rounded to ovate and broader achenes. Additionally, we provide the preliminary conservation status assessments using IUCN Red List categories and criteria, as well as an updated checklist and a key for Valeriana species from Southeastern Brazil.