The fern genus Pteridrys is characterized by having free veins and a tooth on each sinus between two pinna or pinnule lobes. Up to now very little attention has been paid to the taxonomy of Pteridrys. In this monographic study we recognize 24 species in four sections, of which 11 species are described as new: P. catenata. P. cicuzzai. P. clarinervis. P. dongshiyongii. P. dorsifixa. P. malesiana. P. nonattingens. P. reticulata. P. triangularis. P. vanderwerffii, and P. wusugongii. These species are distributed in tropical (and subtropical) Asia with Vietnam being the most species-rich country known so far with ten species. A key to all species is provided, all species are described and illustrated, and information on their distribution and habitats is given.

Three taxa from Taiwan in the Pteris cretica group (Pteridaceae) have extremely wide pinnae that are greater than two cm wide. Leaf and spore morphology, complemented with molecular phylogenetic results, indicate these three taxa are new for Taiwan. Compared with similar species in adjacent areas, they are described here as one new record, Pteris esquirolii, and two new species, P. rugosifolia and P. subesquirolii. Pteris rugosifolia has chartaceous and wrinkled laminae, and P. subesquirolii, similar to P. esquirolii, has coriaceous and flat laminae. Furthermore, there are differences in elevation among the three species. A table with morphological diagnostic features of these three species is included, as well as a dichotomous key for the species of the Pteris cretica group species occurring in Taiwan.

Mesadenus displays an odd disjunction, with most species found in the southeastern USA, the Caribbean, and Mexico south to El Salvador, and two outliers occurring in southeastern Brazil. A recent molecular phylogenetic study showed that, as currently delimited, Mesadenus is polyphyletic, and further study of this little-known genus is required. Here we assessed relationships in Mesadenus and to other genera conducting a cladistic parsimony analysis of nucleotide sequences of nuclear (ITS) and plastid (matK-trnK, trnL-trnF) DNA for an enlarged sample of taxa, including five out of six currently accepted species of Mesadenus and representatives of nearly all (36 out of 41) genera of Spiranthinae, plus suitable outgroups. A detailed comparison of vegetative and floral attributes of relevant taxa was also conducted. Our results confirm the polyphyly of Mesadenus and support the creation of a new genus, Espinhassoa, to include Brazilian ‘Mesadenus’ glaziovii and ‘M.’ rhombiglossus (as Espinhassoa glaziovii and E. rhombiglossa, respectively). An identification key, descriptions, and illustrations of the two species herein included in Espinhassoa are provided.

The phylogenetic position of a rare orchid species, which was described by Mansfeld from the Brazilian Amazon, is discussed. Although originally described under Epidendrum despite having a column that is not fully adnate to the lip claw, a feature not common in this genus, Epidendrum apuahuense has been transferred to Encyclia and Prosthechea by other authors. About 90 yr after its description, we found a new population of this species in Brazil, which allowed us to study its taxonomy. A phylogenetic reconstruction was performed using nuclear (ITS rDNA) and plastid (matK exon, rpl32-trnL spacer, trnL intron, and trnL-trnF spacer) datasets, aiming to clarify the generic placement of this taxon. Our results strongly support keeping E. apuahuense under Epidendrum. We also neotypify this name, since the original specimens were destroyed and no illustration is available. The morphological affinities of E. apuahuense and allied taxa are discussed.

In the context of the revision of Amaryllidaceae tribe Griffinieae that we are preparing, we describe and illustrate a new species, Griffinia albolineata, known from a single fragment of the Atlantic Forest in the Brazilian State of Minas Gerais. It is distinguished by the foliar blade with a whitish longitudinal stripe and long-acuminate apex, unique features among the large-sized species of the genus. Additionally, we present a taxonomic reassessment of G. intermedia, described two centuries ago and historically of very uncertain identity. We provide a description and detailed distribution data, previously unpublished records, and photographs of the species in its natural habitat. We also compare the foliar anatomy and surface micromorphology of the two species. The conservation status of the two species is informally evaluated, and both are tentatively considered endangered. An identification key to the large-sized species of the genus is presented.

Mesosetum (Poaceae, Arthropogoninae) is a Neotropical genus with its greatest diversity in Brazil, which has 22 of the 25 recognized species, 14 of which are endemic to this country. One more endemic species, Mesosetum filgueirasii, here described, is allied to M. penicillatum because it has the lower lemma covered by an indumentum in tufts. This work establishes the distinction between these species and provides the anatomical description of the leaf blade of M. filgueirasii. The new species is known only from the area called “Garganta,” located on the border of the Brazilian states of Tocantins and Bahia. It grows in Cerrado vegetation, in eroded soil. This is the first report of anatomical data supporting taxonomic studies in this genus.

The taxonomically difficult genus Polylepis (Rosaceae) contains several problematic species complexes, including one around P. sericea. We here reevaluate species boundaries in this complex based on morphological characters and climatic niches. We recognize five species within the P. sericea complex, based primarily on leaf characters: P. albicans (northwestern Peru), P. argentea (central Peru) described here, P. canoi (southeastern Peru to central Bolivia), P. ochreata (Ecuador to southernmost Colombia), and P. sericea (Venezuela to central Colombia). We provide full synonymy, diagnostic notes, lists of selected specimens examined, and a key to the species of the complex.

Dalechampia macrobractea is a new species of Euphorbiaceae described from Tanzania and Zambia, Africa. It is similar to D. capensis due to having the deeply lobed leaves and three-lobed involucral bracts, but differs from this species in the size and shape of the leaves, number of pistillate bracteoles, and the absence of glandular trichomes on the margin of the pistillate bracteoles. We place it in Dalechampia sect. Dalechampia because the staminate involucel is two-lipped and the laminar staminate bracteoles are entire. Illustrations and comments about its geographical distribution and habitat are also provided.

Two new species of Cnidoscolus section Calyptrosolen (Euphorbiaceae) are proposed from Mexico. Both are drought deciduous shrubs that occur in tropical deciduous forest and are endemic to the country. Cnidoscolus eglandulatus is known only from the state of Oaxaca. It is noteworthy in lacking a petiolar gland. Cnidoscolus infernidialis is endemic to the state of Michoacán. The conservation statuses of both species were evaluated following IUCN and MER criteria, and they were determined to be critically endangered (unofficially) and endangered, respectively. A key also is provided to identify all of the known Mexican species of Cnidoscolus, which occur in C. sections Jussieuia and Calyptrosolen. Future collectors of the genus are encouraged to describe the petiolar glands when they are fresh, given their importance as diagnostic characters.

As part of taxonomic studies of the genus Acalypha in eastern Brazil, we describe here a new species, Acalypha almadinensis, from the Atlantic Rain Forest, in the states of Bahia and Minas Gerais. This species is morphologically similar to Acalypha brasiliensis and A. accedens, but differs from both mainly by its fleshy pistillate bracts and vinaceous lower leaf surface.

Microlicia longirostrata (Melastomataceae), a new species from Goiás, is described and illustrated, and a discussion on leaf anatomy is also provided. The new species resembles M. consimilis and M. psammophila, but differs from them in having an indumentum with both short-stalked, spherical, glandular trichomes and long-stalked, glandular emergences, polysporangiate anthers and antesepalous stamens with a very long beak (2–2.5 mm long), and annular collenchyma on the adaxial region of the midrib.

Pennellia yalaensis, a new species of Brassicaceae from Jujuy Province in Argentina, is described and illustrated, and its phylogenetic relationships with nearest relatives are discussed. This novelty is morphologically related to P. boliviensis and P. brachycarpa, which also grow in the Central Andes of Argentina. However, P. yalaensis clearly differs from both species by the plant height, inflorescence type, and petal length. In addition, trichomes of the basal leaves distinguish the new species from P. boliviensis, and fruit length and number of ovules/seed from P. brachycarpa. Phylogenetic analyses, based on DNA sequences of nuclear ITS and plastid trnL-F regions, confirmed these affinities.

We describe Aspidosperma huberianum, a new species from the Brazilian Amazon. The new taxon is morphologically similar to A. darienense, but can be distinguished readily by characters of the leaf (including venation), flower (including calyx lobe number and indument of the corolla and ovary), pollen, fruit, and seed. We provide a taxonomic description, pollen characterization, illustration, photographs, and a distribution map for the new taxon, as well as information on its conservation status, habitat, and phenology.

A new species, Mycetia suedixieana, from Samar, Philippines, is described and illustrated. It is an unusual, heavily-branched shrub thriving on moist limestone that is easily distinguishable from other Mycetia species in multiple aspects of its morphology. A key to the known species of Philippine Mycetia is also provided in this study.

Cephalanthus belongs to Rubiaceae tribe Naucleeae, and is characterized as shrubs to a small trees, mainly from the lowlands, with verticillate leaves. We hypothesized that the foliar morphoanatomy of Cephalanthus species provides characters informative to our taxonomic study, and that their leaves present adaptations to waterlogged habitats. To test these hypotheses our aims were to describe the macro- and micromorphology and anatomy of leaves in all Cephalanthus species. We describe and characterize leaf disposition, shape, size of blade and petiole, characteristics of the epidermis and indumenta, including the micromorphology of the cuticle and stomata, and the types of leaf domatia, if present. The anatomy of the petiole and leaf blade was also analyzed, including the mesophyll, vascular systems, ontogeny of the stomata, presence and typification of oxalate of calcium crystals, and their distribution in the foliar tissues. Uniformity in the morphoanatomical characters allows us to define the genus Cephalanthus, but inside this uniformity we can also differentiate between the species by means of a dichotomous key. The presence of domatia in pockets in C. occidentalis, in contrast to the tuft of hairs in C. salicifolius and C. tetrandrus, shed light on the taxonomic delimitation of the former because historically they were considered a single species. Cephalanthus species show variability in micromorphological characters, but have a strong uniformity in anatomical organization. The leaves of Cephalanthus show adaptations to seasonal environments; some are typical hydromorphic traits while other reflect adaptations to their heliophilic habitat and tolerance to dry periods.

Uncovering phylogenetic diversity is important, but not simple. A species complex is defined by different taxa with close evolutionary relationships harbouring limited morphological and/or genetic gaps. One such example exists within neotropical Utricularia sect. Foliosa, which is a taxonomically problematic assemblage composed of three currently recognized species: Utricularia amethystina. U. tricolor, and U. tridentata. The section type, Utricularia amethystina, contains 27 synonymized names. Morphological variation across the three species and associated synonyms suggests that previous taxonomic studies had underestimated taxonomic diversity. To examine taxonomic limits we sampled multiple accessions representing the three currently recognized species and many of the synonymized taxa classified under U. amethystina. We reconstructed a molecular phylogeny using three plastid regions (rps16, trnL-F, trnD-T) and nuclear ribosomal ITS. The three plastid markers produced similar phylogenetic topologies, and the combined plastid and nuclear phylogenies were congruent. The combined analysis provided strong support for most taxa previously identified through morphological analysis, also containing distinct groupings that likely represent both putative new species, and synonyms that are not monophyletic under the type accessions to which they had previously been relegated. The current analysis also shows a sister relationship between U. amethystina s. s. and U. tricolor, with U. tridentata found to be nested within the sister clade. Our results uncovered previously underestimated phylogenetic diversity within Utricularia sect. Foliosa, possibly driven by isolation factors such as specific phytophysiognomy across the varied habitats of the broad distribution across Central and South America.

The polymorphic genus Merremia has been shown to be polyphyletic. In 1980, Xenostegia was separated from the first, based on its longitudinally dehiscing anthers, stigmas with long tapering papillae, and non-spiny, pantoporate pollen, and accommodated two species in the Old World tropics. A recent molecular study and subsequent review of the tribe Merremieae resulted in the distinction of seven genera and corroborated the delimitation of Xenostegia at genus level, with three more species added to it. During fieldwork carried out in 2015 and 2016 in Lomami National Park, Democratic Republic of the Congo, material was collected of a Convolvulaceae species with pinnatifid leaves that was morphologically very close to Xenostegia sapinii, but deviated notably in sepal shape and corolla length. Closer examination revealed additional distinctive characters leading to the conclusion that it represents a distinct taxon new to science. Its pantoporate pollen, longitudinally dehiscing anthers, and stigmas with long papillae seem to confine its placement in Xenostegia. However, its most striking feature is the presence of two free styles, a character otherwise not present in the subfamily Convolvuloideae. The results of our molecular phylogenetic analyses confirmed our hypothesis on our new taxon being a member of Xenostegia. The observed incongruence between the nuclear and plastid-based trees might indicate that the new taxon has a hybrid origin. Based on all evidence, it is recognized at species level, Xenostegia lomamiensis, and it is formally published, along with a full morphological description, illustration, habitat data, and an informal IUCN Red List assessment. A key to the species of Xenostegia in central Africa is provided.

Rocky outcrops surrounded by vegetation in northeastern Brazil form special ecosystems of high species richness and endemism and represent priority areas for biodiversity studies and conservation measures. Floristic surveys of rocky outcrops in the State of Ceará resulted in the identification of a new species of Solanum from the Thomasiifolium clade. Its morphological description, geographic distribution, habitat, ecology, informal conservation status, and environmental suitability models are provided and discussed.

A new species of Artemisia (Asteraceae: Antemideae) from Xizang, China, A. baxoiensis, is described, illustrated, and discussed based on morphological, micromorphological, and molecular phylogenetic evidence. It grows in the Nu Jiang dry-hot valley and is narrowly distributed. This plant is similar to Neopallasia pectinata, but different in capitula and indumentum. Artemisia baxoiensis has a distinctive morphology with a pectinately pinnatisect leaf blade and unusually dense glandular hairs.

Moquiniastrum glabrum is here described as a new species of Tribe Gochnatieae from the Chapada dos Veadeiros National Park, Goiás, Brazil. The new species is recognized by having a monoecious reproductive system, glabrous branches and leaf blades, 9–11-seriate involucral bracts, and 30–35 florets per capitulum, all of which are bisexual. Illustrations, comments, a preliminary conservation status, and an updated key to the taxa of Moquiniastrum are provided.

Two new species, one Lepidaploa and one Critoniopsis, were found in two diversity hotspots, the municipalities of Santa Teresa and Governador Lindenberg, in the Atlantic Forest, Espírito Santo State, Brazil. Lepidaploa congesta differs from other Brazilian species of the genus by its indumentum, leaf apex, inflorescences, and the apex of involucral bracts. Critoniopsis canaliculata differs from the other Brazilian species of the genus by its habit, branches, phylotaxy, petiole morphology, leaf color, cypselae indumentum, and pappus color. According to an informal assessement performed by applying criteria of the IUCN red list, Critoniopsis canaliculata should be included in the Critically Endangered (CR) category, whereas Lepidaploa congesta is Data Deficient (DD). These discoveries show that the current knowledge on biodiversity in Espírito Santo State still is incipient, even in sites with decades of biological inventories, such as Santa Teresa.

We report Eryngium arenosum (Apiaceae, Saniculoideae), a new species from Texas, USA. This new species is differentiated from E. nasturtiifolium, the most similar species, by characters of the capitule (color, shape, size, number of flowers), lengths and shapes of the involucral and floral bracts, presence or absence of a coma, length of the calycine scales relative to the sepals, and habitat preferences. We describe and illustrate these differences, and provide a morphological description, information on phenology, geographical distribution, and habitat, and illustrations of the new species.

Hydrocotyle taxonomy is poorly resolved due the traditional assessment of leaf morphology that has imposed difficulties to species delimitation and prompted the recognition of several infraspecific taxa. Hydrocotyle quinqueloba comprises ten infraspecific taxa that differ mainly by the shape of their leaf blade. The species complex occurs in montane forests of the Andes and eastern Brazil, along the Atlantic Forest and Cerrado domains. However, the geographic distribution of the taxa under H. quinqueloba is poorly known, and their supposedly continuous morphological variation remains unverified. Here we analyze the morphological variation and documented correlated differences in geographic distribution of H. quinqueloba to assess whether they support the delimitation of distinct species or the recognition of infraspecific taxa. For this task, we applied landmark-based geometric morphometrics (GM) to leaves and traditional morphometrics to other structures of specimens of H. quinqueloba. Procrustes analysis of variance (Procrustes ANOVA) indicated that variation of leaf blade shape was weakly associated with geography and was mainly explained by taxa themselves. In contrast, variation of leaf blade size was significantly (p < 0.001) associated with geography, but variation at the specimen level could account for it. Principal component analysis (PCA) of leaf blade shape indicated that taxa differed mainly by the angle and relative size between median and lateral primary veins, by the space between the petiole insertion and middle lobe's sinuses, and by the width of the middle lobe's base. Canonical variate analysis (CVA) indicated significant (p < 0.01) differences among seven infraspecific taxa that formed groups defined by leaf blade shape. Linear discriminant analysis (LDA) of 11 morphological characters separated five groups of taxa, which displayed significant (p < 0.001) differences among each other. Based on that, we propose an updated taxonomic treatment that restricts the circumscription of H. quinqueloba to plants from the Andes and accepts four species from eastern Brazil.