Distribution pattern in the rupiculous genus Orthophytum (Bromelioideae/Bromeliaceae) reveals high microendemicity in different types of rocky outcrops.

This study aimed to recognize the biogeographic patterns, richness, and diversity levels of the Brazilian endemic genus Orthophytum and identify their biotic components through a parsimony analysis of endemicity (PAE), to better understand the evolutionary history of this group and develop strategies for the conservation of its species. We prepared a database for the 54 currently known species of Orthophytum, including their geographical locations as obtained from digital databases of the principal herbaria of Brazil, Europe, and the USA. A parsimony analysis of endemicity (PAE) was used to delimit the areas of endemism based on two grids' sizes (1º x 1º and 2º × 2º). The majority rule consensus tree resulting from the PAE indicated three areas of endemism with high bootstrap, diversity, and richness indices: the northern portion of the Espinhaço Range, the southern portion of the Espinhaço Range, and the central portion of the Atlantic Forest. The recognition of those distribution patterns reveals a high number of microendemic species, which is discussed here.

Down, then up: non-parallel genome size changes and a descending chromosome series in a recent radiation of the Australian allotetraploid plant species, Nicotiana section Suaveolentes (Solanaceae).

BACKGROUND AND AIMS: The extent to which genome size and chromosome numbers evolve in concert is little understood, particularly after polyploidy (whole-genome duplication), when a genome returns to a diploid-like condition (diploidization). We study this phenomenon in 46 species of allotetraploid Nicotiana section Suaveolentes (Solanaceae), which formed <6 million years ago and radiated in the arid centre of Australia. METHODS: We analysed newly assessed genome sizes and chromosome numbers within the context of a restriction site-associated nuclear DNA (RADseq) phylogenetic framework. KEY RESULTS: RADseq generated a well-supported phylogenetic tree, in which multiple accessions from each species formed unique genetic clusters. Chromosome numbers and genome sizes vary from n = 2x = 15 to 24 and 2.7 to 5.8 pg/1C nucleus, respectively. Decreases in both genome size and chromosome number occur, although neither consistently nor in parallel. Species with the lowest chromosome numbers (n = 15-18) do not possess the smallest genome sizes and, although N. heterantha has retained the ancestral chromosome complement, n = 2x = 24, it nonetheless has the smallest genome size, even smaller than that of the modern representatives of ancestral diploids. CONCLUSIONS: The results indicate that decreases in genome size and chromosome number occur in parallel down to a chromosome number threshold, n = 20, below which genome size increases, a phenomenon potentially explained by decreasing rates of recombination over fewer chromosomes. We hypothesize that, more generally in plants, major decreases in genome size post-polyploidization take place while chromosome numbers are still high because in these stages elimination of retrotransposons and other repetitive elements is more efficient. Once such major genome size change has been accomplished, then dysploid chromosome reductions take place to reorganize these smaller genomes, producing species with small genomes and low chromosome numbers such as those observed in many annual angiosperms, including Arabidopsis.

Distribution patterns, endemism, richness and diversity of Convolvulaceae in the Espinhaço Range, Brazil.

The Espinhaço Range is known for its unique plant diversity and richness of endemic species. We identified the distribution patterns, areas of endemism, floristic similarity, and the areas of richness and diversity of Convolvulaceae within the Espinhaço Range by analyzing a database of approximately 2600 occurrence records. One hundred and eighty-four taxa were categorized into one of four distribution patterns: continuous, disjunct, centered in the Bahia sector, and centered in the Minas Gerais sector. Nineteen Convolvulaceae species are endemic to Espinhaço Range. Endemic species had all of the different distribution patterns. Parsimony analysis of endemism indicated two main centers of endemism for the family: one in the Minas Gerais sector, on the Diamantina Plateau, and another in the Bahia sector, in the Chapada Diamantina. The floristic similarity, richness, and diversity analyses evidenced a principal group in each portion, mainly concentrated in the Chapada Diamantina, and secondarily in the Iron Quadrangle. Such studies are important both for understanding biodiversity and for decision-making in public conservation policies.

Remarkable disjunctions in Ipomoea species (Convolvulaceae) from NE Brazil and Central America and their taxonomic implications.

Recent collections of Ipomoea from North East Brazil have revealed a number of unexpected disjunct distributions. The most remarkable is that of I. eremnobrocha D. F. Austin, previously thought to be endemic to Panama but now known from three states in NE Brazil. Revision of Panamanian material named I. eremnobrocha unexpectedly showed that two distinct species had been treated under this one name. Specimens from the Chagres National Park area in Panama are described as a new species under the name I. isthmica J. R. I. Wood & Buril while I. eremnobrocha is retained as the correct name for the plant from the Altos de Campana in Panama and NE Brazil. An amended description of this species is given and a table of differences between the related species is provided. Two recently described species from Bolivia, I. graniticola J. R. I. Wood & Scotland and I. chiquitensis J. R. I. Wood & Scotland are recorded from NE Brazil several thousand km from their type localities. Attention is drawn to the role of granite inselbergs as sites of species with a disjunct distribution. A possible relative of I. chiquitensis is described as a new species from NE Brazil under the name I. melancholica J. R. I. Wood & Buril. The new species are illustrated with line drawings and maps of the unusual distribution patterns are provided.

Leaf and stem micromorphology of Jacquemontia evolvuloides (Moric.) Meisn. (Convolvulaceae) populations: New insights for taxonomic classification using light and scanning electron microscopy.

Morphoanatomical studies can provide useful and relevant information to support taxonomic groupings. Jacquemontia evolvuloides shows great morphological variability, which has led to numerous taxonomic classifications. To determine if anatomical characters can be used to recognize operational taxonomic units within populations of that species, we analyzed the leaves and stems of 22 populations using light and scanning electron microscopy. The variability of the analyzed characters allowed the grouping of these populations into five morphotypes. The presence of paracytic stomata, laticiferous canals, and stellate trichomes can be considered diagnostic characters of J. evolvuloides. The presence and types of epicuticular waxes, as well as a layer similar to palisade parenchyma in the petioles and stems, the classifications of glandular trichomes, and new types of stomata (anomocytic, anomotetracytic, and brachyparatetracytic) are reported here for the first time for Jacquemontia. The results discussed here help clarify the classification of this species complex and contribute to the taxonomy of Jacquemontia-a genus that has historically been difficult to define due to its wide morphological variation at the species level. RESEARCH HIGHLIGHTS: Seven types of epicuticular waxes were identified among J. evolvuloides specimens: granules, threads, entire platelets, coiled rodlets, fissured layers, membranous platelets, and tubules. Six types of trichomes were observed among J. evolvuloides populations: stellate, malpighiaceous, sessile peltate glandular, short pedunculate glandular, stipitate-glandular, and capitate glandular. We observed that six populations of Jacquemontia evolvuloides located in the Brazilian Caatinga domain have unprecedented sessile peltate trichomes restricted to the main leaf midrib, which were only observed under light microscopy.

A threatened new species of Ipomoea (Convolvulaceae) from the Brazilian Cerrado revealed by morpho-anatomical analysis.

A new species of Ipomoea, endemic to the Cerrado domain in Maranhão, Brazil, is described. Ipomoea maranhensis D.Santos & Buril, sp. nov. has been misidentified as I. burchellii Meisn. in several herbaria. Even though both species have oblong, pubescent leaves, they can be distinguished by morpho-anatomical characters. We present a diagnosis, complete description, illustration, taxonomic comments, conservation status and distribution map.

Flora of Pernambuco, Brazil: Tabebuia alliance and tribe Jacarandeae (Bignoniaceae) / Flora de Pernambuco, Brasil: Aliança Tabebuia e tribo Jacarandeae (Bignoniaceae)

Abstract: Bignoniaceae is a Pantropical plant family that includes 82 genera and 830 species of trees, lianas, and shrubs. The Tabebuia alliance (14 genera and 147 species) and tribe Jacarandeae (2 genera and 50 species) are both Neotropical and represent the largest clades of trees and shrubs in the family. Here, we present a taxonomic treatment for these two clades for the state of Pernambuco, Brazil. Overall, we documented 23 species distributed in seven genera, i.e., Cybistax Mart. ex Meisn., Godmania Hemsl., Jacaranda Juss., Handroanthus Mattos, Sparattosperma Mart. ex Meisner, Tabebuia Gomes ex DC., and Zeyheria Mart. Six taxa are new records for the state, i.e., Cybistax antisyphilitica (Mart.) Mart., Handroanthus capitatus (Bureau & K. Schum) Mattos, Handroanthus umbellatus (Sond.) Mattos, Jacaranda cuspidifolia Mart., Sparattosperma catingae A.H. Gentry, and Tabebuia stenocalyx Sprague & Stapf. Furthermore, S. catingae, previously thought to be endemic to the Caatinga of Bahia, was documented for the first time in the Atlantic Forest domain. We present identification keys and taxonomic descriptions for all genera and species, as well as provide illustrations and information on the geographic distribution, habitat, and phenology for all species.

Resumo: Bignoniaceae é uma família de plantas pantropicais que inclui 82 gêneros e 830 espécies de árvores, lianas e arbustos. A aliança Tabebuia (14 gêneros e 147 espécies) e tribo Jacarandeae (2 gêneros e 50 espécies) são ambas neotropicais e representam os maiores clados de árvores e arbustos na família. Aqui, apresentamos um tratamento taxonômico para estes dois clados para o estado de Pernambuco, Brasil. No geral, nós documentamos 23 espécies distribuídas em 7 gêneros, i.e., Cybistax Mart. ex Meisn., Godmania Hemsl., Jacaranda Juss., Handroanthus Mattos, Sparattosperma Mart. ex Meisner, Tabebuia Gomes ex DC., e Zeyheria Mart. Seis táxons são novos registros para o estado, i.e., Cybistax antisyphilitica (Mart.) Mart., Handroanthus capitatus (Bureau & K. Schum) Mattos, Handroanthus umbellatus (Sond.) Mattos, Jacaranda cuspidifolia Mart., Sparattosperma catingae A.H. Gentry, e Tabebuia stenocalyx Sprague & Stapf. Além disso, S. catingae, que anteriormente se pensava ser endêmica da Caatinga da Bahia, foi documentada pela primeira vez no domínio da Mata Atlântica. Nós apresentamos chaves de identificação e descrições taxonômicas para todos os gêneros e espécies, assim como fornecemos ilustrações e informações sobre a distribuição geográfica, habitat e fenologia para todas as espécies.