Ana Kelly Koch

Two new species of Melastomataceae, Tibouchina caducifolia and T. dispar , are described from the Parque Nacional da Chapada dos Guimarães (PNCG), Mato Grosso, Brazil. Both show characters typical of the Southern clade of Tibouchina , including stamens with villose filaments and villose pedoconnective appendages, suggesting that they likely belong to this clade, although they have not yet been included in a phylogenetic analysis. Morphological descriptions, high‐resolution photographs, scanning electron micrographs, photographic plates, distribution maps, and preliminary conservation assessments are provided. Comparisons with morphologically similar taxa are included, highlighting diagnostic traits that facilitate identification. Additionally, we present a detailed account on the globoid or fusiform stem galls that are frequently observed on the basal portions of the branches in T. caducifolia , and represent a conspicuous feature that may assist in the recognition of the species. Both species are endemic to the PNCG, occurring in rupestrian savannas (‘cerrado rupestre') and associated rupestrian grasslands (‘campos rupestres'), with restricted ranges and specialized rupestrian habitats. Due to the limited number of georeferenced records and insufficient data on population size, trends, and response to fire, both species are preliminarily assessed as ‘Data Deficient' (DD) according to IUCN criteria. These findings reinforce sandstone outcrops in the Cerrado of central Brazil as centers of plant diversity and endemism, underscoring the importance of continued taxonomic research in underexplored areas.

Zomicarpella maculata N.E.Br. (Araceae, Caladieae) a rare species previously known only from Cuzco, Peru, is here recorded for the first time from Brazil. The species was found in a semi-deciduous forest within the Estação Ecológica da Serra das Araras, Mato Grosso. This represents an eastward range extension of over 1,500 km. Diagnostic morphological characters, habitat information, taxonomic notes, and an updated distribution map are provided. This finding significantly expands the species’ range and underscores the critical role of protected areas in conserving rare taxa.

In the present study, we describe and illustrate Mormodes benelliana, a new species found in the southwest region of the Brazilian state of Mato Grosso. This species occurs as an epiphyte in the transition between the Amazon and Cerrado domains. Mormodes benelliana is similar to M. hoehnei, but differs by having smaller pseudobulbs, inflorescences longer than the pseudobulbs, conspicuous peduncle, yellowish-brown and brown-vinous striped flowers, with a large-elliptic to ovate, glabrous lip.

In this work, we propose the second-step lectotypification of the name Billbergia meyeri and the lectotypification of the name Billbergia leucantha. We also discuss the geographic distribution of Billbergia meyeri.

The historical background of studies on Brazilian Orchidaceae dates back almost 400 years. In this review, we provide an overview of the current knowledge on Brazilian Orchidaceae across three thematic axes: 1. diversity, distribution, and endemism; 2. taxonomy and systematics; and 3. structural, genetic, and ecological characterization. Brazil harbors five naturalized and 202 native genera, of which 23 are endemic to the country. There are currently 2515 accepted species (out of 9907 species names). Among the 7218 synonyms, 3915 are heterotypic, yielding a synonymy rate of 60.9%. Brazil is the second country in orchid endemism with 1540 endemic species. Apostasioideae is not present in Brazil, but the remaining four orchid subfamilies are represented by 16 tribes and 23 subtribes. The richest phytogeographic domain is the Atlantic Forest (1398 spp.), followed by the Amazon Forest (784 spp.) and Cerrado (656 spp.). The richest subtribes are Pleurothallidinae (642 spp.), Laeliinae (397 spp.), and Oncidiinae (283 spp.). Moving beyond a purely taxonomic and phylogenetic framework, this work offers a comprehensive synthesis of Brazilian Orchidaceae, encompassing the state of the art in cytogenetics, anatomy, population genetics, reproductive biology, and pollination. Despite these advances, there are pronounced disparities among regions, taxa, and research approaches. The persistence of these shortfalls highlights the urgent need for integrative research frameworks. Future progress in Brazilian orchidology depends on the strengthening of collaborative networks and interdisciplinary approaches.

Justicia vitoriae, a new species of Acanthaceae, is described and illustrated from the Amazon Forest in the states of Mato Grosso and Pará, Brazil. The species is assigned to Justicia sect. Simonisia based on its dense capitate inflorescences, elongate bilabiate corollas, and robust capsules containing smooth, spherical seeds. Morphologically, it is closely related to J. riedeliana and J. matogrossensis, but can be distinguished by its shorter and broader bracts and bracteoles, which mostly cover the calyx, by its narrowly elliptic to lanceolate bracteoles, and by its relatively large flowers. The floral morphology strongly indicates ornithophily, with hummingbirds likely serving as primary pollinators. This species inhabits the understory of various forest types in the southern Amazon, particularly near the Amazon–Cerrado transition zone, a region where deforestation has intensified in recent years. Despite this environmental pressure, J. vitoriae is currently assessed as Near Threatened (NT), as it is still represented by a relatively large number of populations.

Tibouchina triprovincialis is a new species collected in the Brazilian states of Amazonas, Mato Grosso, and Rondônia. All gatherings from Amazonas and Rondônia come from the “Parque Nacional dos Campos Amazônicos”, while the single gathering outside it comes from northwestern Mato Grosso. Dense and extensive populations of this small shrub occur in “hyperseasonal savannas”, i.e. savannic enclaves in the middle of the Amazonian rainforest, with a thick herbaceous layer and very few shrubs or trees, growing on poorly drained soils. Tibouchina triprovincialis differs from both T. aspera and T. spruceana by the smaller leaves, with shorter petioles, 0.6–1.5 mm long (vs. 3–10 mm in T. spruceana, 2–10 mm in T. aspera) and blades 5–11 mm long (vs. 20–50 mm in T. spruceana, 20–80 in T. aspera), the abaxial surface densely covered with broad scales that conceal the surfaces of veins and the actual surfaces between the veins (vs. moderately covered with slender scales or trichomes that do not conceal the surfaces beneath, on both the veins and the actual surfaces between the veins). As for extinction risk, we suggest that T. triprovincialis should be regarded as “Least Concern” (LC).

A new species of Orinoquia (Gonolobinae, Apocynaceae) from the state of Mato Grosso, in the Central-West region of Brazil is described and illustrated, making this the first record of this genus in the country. Orinoquia brasiliensis is morphologically similar to O. yanomamica, which is known to occur only in Venezuela, but differs mainly by branches only with long simple trichomes, longer pedicels and sepals, and ovate corolla lobes; the follicles of the genus are here described for the first time. The new species is endemic to the Cerrado and known from only one population; therefore, its conservation status is suggested as Data Deficient (DD), according to IUCN criteria. A distribution map with the occurrence of the two known Orinoquia species is presented, as well as taxonomic comments, images, an illustration, a comparative table with the main features to distinguish the genus, and an identification key to the Gonolobinae of Mato Grosso.

Calea is a neotropical genus of Asteraceae, Neurolaeneae, with 93 species in Brazil. A new species of Calea from Mato Grosso state, Brazil, is described here as C. grandibracteata. This new species is characterized by having a conspicuous and larger pair of foliaceous phyllaries compared to Calea hatschbachii and Calea rupicola. An identification key for the Calea species recorded in Mato Grosso, illustration, photo plates, distribution map, and taxonomic comments on the new species are provided. In addition, we confirm the occurrence of Calea polycephala in Mato Grosso.

Pavonia neuropetala, a new species from the Cerrado of southwestern Mato Grosso, is hereby described and illustrated. It belongs to Pavonia subgenus Pavonia section Lopimia f and its conservation status was assessed as Critically Endangered. Its morphological affinities with related species are discussed, images, a table with morphologic data, and a key of species from Pavonia section Lopimia from Mato Grosso are provided.