Pollen morphology of species of Graphistylis B. Nord. (Asteraceae) of Brazil

Abstract

This paper presents the results of a palynological study of the species of Graphistylis that were segregated from Senecio (s.l.) (Senecio sect. Dichroa) and that are all endemic of Brazil. These species are found in mountainous regions of the states of Espirito Santo, Minas Gerais, Paraná, Rio de Janeiro, São Paulo and Santa Catarina. The pollen grains of eight species were acetolyzed and analyzed and photographed using light microscopy. Unacetolyzed pollen grains were analyzed and photomicrographed using scanning electron microscopy. The current study undertook a palynologically analysis of Graphistylis in order to obtain information useful for making a better ranking of these genus. The results show medium-sized pollen grains that were oblate spheroidal or prolate spheroidal and subtriangular amb and tricolporate. The pollen grains possessed lalongate endoapertures with a median constriction and the presence of costa in only two species. The exine is echinate with a varying number of spines in the apocolpium region around the central spine in polar view. The spines are short with basal perforations at varying distances. Although the morphology of the pollen of species of Graphistylis is very similar, multivariate analysis highlights the importance of quantitative traits in distinguishing species.

Spore diversity among species of Blechnaceae in the Atlantic Forest

“…All spores were randomly chosen from standard material on a minimum of three different slides. Measurements of standard and comparative material followed well established methods (Souza et al 2016;Sousa et al2017;Almeida et al 2018).…”

Palynotaxonomy of species of Dendrophorbium (Asteraceae: Senecioneae) occurring in Brazil

“…The authors described pollen grains as medium-sized, ranging in shape from suboblate to pro-late, 3-colporate, with lalongate endoaperture and cavea. Souza et al (2016) analyzed eight species of the genus Graphistylis and identified pollen as medium in size, with shapes ranging from oblate-spheroidal to prolate-spheroidal, 3-colporate, echinate exine, with conical echinae presenting perforations at the base, and an apertural region involving the colpus. Dendrophorbium and Graphistylis were previously subordinate to Senecio , explaining the similarity between their pollen and demonstrating the homogeneity of the tribe.…”

“…Two factors were considered in the analysis: the percentage of information (variables) needed to form groups and the final number of groups. A dendrogram was constructed using Euclidean distances (Caccavari et al 2008) and Ward's linkage method (Souza et al 2016).…”

“…and, less commonly, of other recent and fossil palynomorphs. In Brazil, important contributions to the palynology of Asteraceae were made by Salgado-Labouriau (1973); Melhem et al (2003); Mendonça and Gonçalves-Esteves (2000); Mendonça et al (2002, 2007a, 2007b, 2009, 2010); Cancelli et al (2005, 2010); Magenta et al 2010; Souza et al (2016); Souza-Souza et al (2016); Siniscalchi et al (2017); Moreira et al (2018); Soares et al (2020) and Souza-Souza et al (2021, 2022). This study aimed to morphologically characterize the pollen grains of the 13 species of Dendrophorbium that occur in Brazil, of which 11 were described palynologically, for the first time.…”

Pollen morphology of some species of Spermacoceae s.s. (Rubiaceae) of the Atlantic Forest, Rio de Janeiro, Brazil

“…Ten similar measurements of pollen grains were made on additional material, from another collection, to check the stability of the data (treated further as comparison material). Whenever possible, comparison specimens were analyzed for confirmation of the obtained results (Souza et al 2016;Marinho et al 2018;Moreira et al 2018;Sousa et al 2018).…”