Tricky Morphology: A New Species of Chamaecrista (Leguminosae) Shows Strong Morphological Convergence Among Not Closely Related Species Found in Similar Habitat

Abstract— Plants from Brazilian campos rupestres usually present morphological strategies that allow them to survive in extreme environments. However, in Chamaecrista (Leguminosae, Caesalpinioideae), one of the most diverse genera in the campos rupestres, needle-like leaflets are rare. Reviewing the species that present such leaf morphology, we describe Chamaecrista acicularis, a new species from the Canastra Range, in the southwestern region of the state of Minas Gerais, Brazil. Phylogenetic analyses revealed that C. acicularis is not closely related to other quite similar needle-like leafleted species and that this trait evolved convergently. We also present comments on the phylogenetic relationships of needle-like leafleted species as well as the evolution of the leaflet amplitude, and a detailed description of C. acicularis alongside illustrations, photos, geographical distribution, a key to the needle-like leafleted species and taxonomic notes on similar species. Additionally, we expand the description of Chamaecrista strictifolia and present an informal conservation status for all needle-like leafleted species.

Lacistema ligiae (Lacistemataceae), a new species from Chapada Diamantina, Bahia, Brazil, with notes on micromorphology

The Flora Neotropica treatment of Flaucourtiaceae s.l., by Sleumer, was a milestone in the study of the group and, consequently, of the families that were subsequently segregated from Flaucourtiaceae. Of these, Lacistemataceae comprise 16 tree-shrub species that usually occur in humid forests. However, specimens from campos rupestres in Bahia State, Brazil, were not analyzed by Sleumer so some morphological variation remained unnoticed. Here, we describe Lacistema ligiae, a new species from the campos rupestres of Bahia, and include notes on leaf venation and pollen morphology of related species. Lacistema ligiae can be recognized by leaf blades with sinuous secondary veins, which are covered by long and adpressed trichomes abaxially, hairy filament and ovary, and a distinct style not exceeding the height of the stamen.

Three New Species of Lychnocephalus (Asteraceae: Vernonieae) from the Serra do Cipó, Minas Gerais, Brazil

Abstract— Lychnocephalus cipoensis, L. grazielae, and L. jolyanus, three new species from the Cerrado of the Brazilian Central Plateau, are hereby described and illustrated. Lychnocephalus is characterized by its tomentose to densely lanate branches, heads organized in third order syncephalia and inner pappus series with twisted setae and narrowed apex. These new species are microendemic in the campos rupestres of Serra do Cipó, state of Minas Gerais, southeastern Brazil, and were previously misidentified as other species of the genus. However, they are distinguished by their habit, leaf arrangement, leaf shape and size, presence or absence of petiole, number of florets per head, and number of pappus series, among other characteristics discussed here. These new species are described and illustrated, their affinities discussed, and a key to all species of Lychnocephalus is provided.

EXTENDING THE LIMITS OF CAMPOS RUPESTRES IN BRAZIL

Campos rupestres are typical ecosystems of rock outcrops with high biodiversity and endemism, located in Brazilian territory, with vegetation analogous in Africa and Australia. The campos rupestres cover deeply dystrophic soils on highlands inserted in Amazon rainforest, Atlantic rainforest and Cerrado biomes. Despite recognition of campos rupestres as a global biodiversity hotspot, little is known its occurrence in dry forests. So, this work aimed to describe vegetable cover and soil properties in highlands associated to rock outcrops on Caatinga biome. A pristine area in Borborema plateau was chosen as study area. Frequency of species and life forms indicate high vegetable density and herbaceous habits predominance. Although the high similarity of species with Caatinga biome, presence of Albizia, Dalbergia, Poecilanthe e Platymiscium indicates a truly distinct floristic composition. Soils are shallower, less fertile and has lower water storage capacity than predominant soils in Caatinga. This work reveals the presence of campos rupestres beyond the areas previously considered favorable to its presence, extending its occurrence to regions of lower precipitation. The occurrence of the campos rupestres is attributed to an additional supply of water from fog in consonance with organic soils. Therefore, areas with similar characteristics should be prioritized to be preserved.

Plant-associated microbiomes promote nutrient turnover in impoverished substrates of a biodiversity hotspot

The substrates of the Brazilian campos rupestres have extremely low concentrations of key nutrients, mainly phosphorus, imposing severe restrictions to plant growth. Regardless, this ecosystem harbors enormous biodiversity which raises the question of how nutrients are cycled and acquired by the biosphere. To uncover the nutrient turnover potential of plant-associated microorganisms in the campos rupestres, we investigated the compositions and functions of microbiomes associated with two species of the Velloziaceae family that grow over distinct substrates (soil and rock). Amplicon, metagenomic, and metagenome-assembled genome sequence data showed that the campos rupestres harbor a novel assemblage of plant-associated prokaryotes and fungi. Compositional analysis revealed that the plant-associated soil and rock communities differed in taxonomic structure but shared a core of highly efficient colonizers that were strongly coupled with nutrient mobilization. Investigation of functional and abundance data revealed that the plant hosts actively recruit communities by exuding organic compounds and that the root-associated microbiomes possess a diverse repertoire of phosphorus turnover mechanisms. We also showed that the microbiomes of both plant species encompass novel populations capable of mobilizing nitrogen and that the substrate strongly influences the dynamics of this cycle. Our results show that the interplay between plants and their microbiomes shapes nutrient turnover in the campos rupestres. We highlight that investigation of microbial diversity is fundamental to understand plant fitness in stressful environments.

Orchidaceae no município de Vitória da Conquista, Bahia: lista de espécies e similaridade florística entre áreas da Bahia e Minas Gerais

Aqui, apresentamos o levantamento das Orchidaceae de Vitória da Conquista, Brasil, e uma análise da similaridade florística entre dez áreas da Bahia e Minas Gerais. Foram encontradas no município 44 espécies de orquídeas, sendo duas novas ocorrências para o Nordeste brasileiro, Acianthera panduripetala e Specklinia hymenantha, além de uma nova ocorrência para o estado da Bahia, Pabstiella seriata. Foram conduzidas análises utilizando o algoritmo UPGMA, coeficiente de Jaccard e Dice, e análise de correspondência. A análise de agrupamento revelou baixos índices de similaridade, exceto para Serra Negra + Parque Estadual do Ibitipoca. Dois grupos se formaram: um de áreas de Florestas Secas e outro grupo que inclui as áreas de Campos Rupestres e de Floresta Ombrófila dos dois estados. Os resultados sugerem que as áreas de mesma fitofisionomia estão mais relacionadas entre si do que com a vegetação do mesmo estado.