Natural hybridization has often been recorded within certain genera of orchids, one of them is Catasetum. During a field study in a forest de igapó in Brazilian Amazon, a new natural hybrid was found, it is here described as Catasetum × sheyllae. Its morphological features, mainly the structures of the lip, are intermediate between those of its putative parent species, C. boyi and C. garnettianum, both observed in sympatry.

This study describes a new natural hybrid of Catasetum, C. × vilhenense, from the State of Rondônia (Brazil) found in ombrophilous forests near the Roosevelt River. The hybrid shows intermediate morphological features between its parental species, C. ariquemense and C. multifidum, with specific differences in floral morphology and inflorescence structure. We provide detailed data on its habitat, ecology, and geographic distribution, and a photographic plate of the hybrid. Given its restricted range, limited to a single locality with an area of occupancy (AOO) of less than 10 km², C. × vilhenense may be Critically Endangered (CR) due to habitat loss and fragmentation. An identification key is also proposed for the species and natural hybrids of Catasetum with symmetrical and parallel antennae in the state of Rondônia, contributing to the understanding and classification of this genus in the Amazon forest.

Hybridization is a process that can occur randomly in nature between different genetically compatible species, as is observed within the genus Catasetum. Thus, this work proposes the description of a new nothospecies found in the lake of Castanho located in the municipality of Careiro Castanho. It is described, illustrated and compared with its parental species: C. gnomus and C. saccatum. In addition, information regarding the distribution, habitat and phenology as well as a key to the natural hybrids occurring in the Brazilian state of Amazonas are presented. Taxonomic notes are presented for five taxa of the genus currently treated as species that, after performing controlled pollination and germination in vitro, have proven to be in reality natural hybrids. Finally, we propose to place C. sanguineum into the synonymy of C. naso.

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.

This study presents a new orchid species of the genus Catasetum belonging to the group of species with symmetrical and parallel antennae. It was found in terra-firme and floodplain forests in the Brazilian states of Amazonas and Pará. We provide a formal description of the new species, images, and notes on distribution, habitat, phenology, flower visitors and preliminary conservation status. We compare it with C. cristatum and C. barbatum, both sympatric and morphologically most similar to the new species. It was preliminarily classified in the Endangered (EN) category according to IUCN criteria based on the extent of occurrence, area of occupation, number of occurrence locations and the risks that the known populations are exposed to (deforestation and predatory collection).

In this study we propose to treat Catasetum meeae and C. lendarium as conspecific based on distinctive features identified in the protologues of both species. We emphasize that C. meeae was never collected again after its description in the 1960s. Here we also invalidate the name C. lendarium because its original description is not in accordance with the Shenzhen Code. We provide a brief taxonomic discussion for the taxon, as well as photographs and information related to distribution and ecology. At this stage the species is evaluated as belonging to the Endangered (EN) category according to IUCN criteria.