Marcetia wilburiana is described and illustrated from the southwestern region of the Chapada Diamantina in Bahia, Brazil, where it appears to be a rare and local species of campo rupestre. Its affinities appear to be with M. ericoides and M. shepherdii, both of which have a wiry subshrubby habit; small, coriaceous, glabrous leaves that are appressed and imbricate on uppermost cauline internodes; and solitary flowers. It differs from both species in having abaxial foliar surfaces that are longitudinally grooved between the callose-thickened margins and midvein, calyx lobes and hypanthia that are moderately to copiously beset with spreading gland-tipped trichomes 0.5–1.0 mm long, and petals that terminate in a persistent glandular trichome. The new species and presumed relatives are mapped and a key is provided to species in the informal ericoid group.

As a precursor to a taxonomic monograph of the Neotropical genus Macleania (Ericaceae: Vaccinieae), a comprehensive nomenclatural index of all published names in Macleania is presented. Valid names and invalid designations (including those used in manuscripts and horticulture), along with their current taxonomic and nomenclatural status, are noted. Confusion among Macleania names caused by protologue deficiencies, poor horticultural practices, and redundant publication in trade journals and sales catalogues is detailed and clarified. Brief historical notes, references to published illustrations, and color illustrations of 19 species are included. Ten first-step lectotypes, seven second-step lectotypes, two neotypes, one example of an isonym, and 14 new synonyms are proposed.

Field and herbarium studies were employed to determine the presence and distribution of Acanthaceae in the Nueva Galicia region of west-central Mexico. With 26 genera and 103 species of native and naturalized taxa, the region is revealed to be one of the richest in Mexico for the family. Twenty-two species of Acanthaceae are treated as endemic to the region, including the newly described Justicia wilburii. Ten new state distribution records are documented from Nueva Galicia regions of Nayarit (4), Michoacán (1), and Zacatecas (5).

Nomenclatural and taxonomic analyses clarify the identities, correct names, and typifications for four previously-described species of Palicourea. A nomenclatural study shows that P. carruthersii is the overlooked oldest name for plants from Central and South America currently called P. microbotrys, and a taxonomic study finds that P. furcata is the oldest name for plants from Central and South America currently called P. longiinvolucrata. The name Psychotria japurensis was inadvertently published twice in the same work, for two different species; this situation has a previously overlooked published resolution, as clarified here: one of Müller's species is correctly called Palicourea iodotricha and the other is P. japurensis. Four new species of Palicourea have been discovered through recent botanical exploration and are described here. Palicourea geminata, from Amazonian Ecuador, is distinctive in its subcapitate inflorescences borne on paired axillary short shoots, well-developed bracts, and white corollas. Palicourea monsalveae, from coastal western Colombia, is distinctive in its glabrous leaves and stems, robust stipules and leaves, and robust and subcapitate inflorescences. Palicourea wilburiana, from the Andes of Ecuador, is distinctive in its sericeous pubescence, relatively large stipules, and subcapitate inflorescences with well-developed bracts. Palicourea woytkowskii, from the Andes of northern Peru, is distinctive in its densely pilosulous leaves and stems and subcapitate inflorescences with well-developed, bright pink bracts.

Cyperus verloovei is described as a new species of Cyperus section Incurvi from northern South America (Guyana and Venezuela). It is most similar to C. grandisimplex from which it is distinguished by its narrower spikelets, smaller scales, and oblong-ellipsoid achenes. A key is provided for all species of section Incurvi in the Neotropical region.

In each of the three edaphic endemic varieties of Phacelia dubia, populations have been observed in weedy roadsides and lawns. Plants in the weedy populations differ ecologically and morphologically from plants in populations historically restricted to granite outcrops or cedar glades. The weedy populations tend to occur in full sun at very high densities, their plants mature at a small size, and they flower approximately one month before nearby outcrop/glade populations. Common garden experiments using plants derived from seeds of P. dubia var. georgiana collected from a weedy site and a nearby granite outcrop showed no size differences between populations when grown under either high light or partial shade conditions. In the shade treatment, plants from both populations failed to flower for the duration of the experiment, but in the sun treatment, significantly more plants derived from the weedy population flowered, and for those plants that flowered, bud production was much higher in plants from the weedy population. A search of herbarium records showed that for each variety, weedy occurrences first appeared between 1972 and 1984. The experimental data showed the weedy phenotype has arisen through a combination of phenotypic plasticity and genetic change, whereas the herbarium record suggests that evolution of the weedy ecotypes is a recent event that has arisen independently in each variety.

The true blueberries (Vaccinium sect. Cyanococcus; Ericaceae) comprise a clade of about nine to 24 species distributed mainly in eastern temperate North America, with one species reaching farther west. Despite extensive study, the systematics and evolution of the group are still poorly understood. Limited morphological variation, multiple ploidy levels of uncertain origin, and natural hybridization all contribute to the challenge. Questionable analytical methods, such as the use of phenetics and an overemphasis on crossing experiments, have further impeded progress. Here we review the history of research on the systematics and evolution of V. sect. Cyanococcus with the aim of clarifying and summarizing hypotheses of species origins and diversification, especially in relation to polyploidy. We also present recent progress from our own work and, on that basis, offer promising lines of investigation with morphological and molecular data. We anticipate that these avenues of research will ultimately clarify patterns of natural species diversity in V. sect. Cyanococcus with benefits for biodiversity studies, conservation, and crop breeding.

North American material from the herbarium of Constantin Samuel Rafinesque-Schmaltz (1783–1840) is reviewed. From this effort 585 specimens were identified from 15 public herbaria, including 450 specimens recorded in online herbarium databases. Future research is planned that will expand this effort to: 1) include all material, not just North American, from Rafinesque's herbarium; 2) determine the original material and type status of each specimen; and 3) develop a Rafinesque herbarium database allowing users to readily search for Rafinesque material.

Gamochaeta (Compositae) is a genus of 50–80 herbaceous species with a center of diversity in South America and with several common, generally weedy species in the eastern United States. Historically, some authors recognized as few as one species in the eastern United States while others have recognized as many as eight. These increased numbers are a product of both naturalization of nonnative species and recognition of new taxa. A study was undertaken with DNA markers to assess whether the putative species of this region exhibit genetic differences and to determine if DNA markers may be useful tools for identification. One nuclear and one plastid region of DNA were sequenced, and unique nuclear markers were found for all eight recognized species and unique plastid markers were found for five of the eight species. These results support the species hypotheses for entities in this region. Unlike other genera of the Compositae (e.g., Solidago) that possess little genetic differentiation in commonly used barcoding regions of DNA, the species of Gamochaeta in the eastern United States can be identified using a single nuclear marker, and several may be identified with a single plastid marker. Given that species of Gamochaeta are naturalizing in many places on Earth, these data will provide an important resource for identification.