ABSTRACT Flowers of Asclepiadoideae are notable for possessing numerous nectaries and elaborate coronas, where nectar can accumulate but is not necessarily produced. Given the complexity and importance of these structures for reproduction, this study aimed to analyze the ontogeny of the corona, the structure and position of nectaries and the histochemistry of the nectar of species of Asclepiadeae. Two types of coronas were observed: androecial [C(is)] and corolline (Ca). The development of the C(is)-type of corona initiates opposite the stamens in all species examined with the exception of Matelea in which it begins to develop as a ring around the filament tube. Despite their morphological variation, coronas typically originate from the androecium. A notable difference among the studied species was the location of the nectaries. Primarily, they are located in the stigmatic chamber, where nectar composed of carbohydrates and lipids is produced. A secondary location of nectaries found in species of Peplonia and Matelea is within the corona, where nectar is produced and stored, composed of carbohydrates and lipids in Peplonia and only carbohydrates in Matelea. The functional role of nectar is related to the location of its production since it is a resource for pollinators and inducers of pollen germination.

Foram analisadas a estrutura e a composição florística de uma formação de restinga arbustiva aberta no Parque Estadual de Itaúnas, ES, e verificada a similaridade entre a flora das formações de restinga arbustiva da Região Sudeste do Brasil. Para o levantamento, foi utilizado o método de intercepto de linha, contemplando indivíduos com altura igual ou superior a 50 cm. Os parâmetros fitossociológicos de frequência e valor de importância (VI) foram calculados. A similaridade da flora das restingas arbustivas da Região Sudeste foi verificada utilizando o índice de Sørensen. Foram encontradas 42 espécies em 28 famílias, sendo Fabaceae e Bromeliaceae as mais ricas (quatro espécies cada). As 10 espécies mais importantes representaram 65,6% do VI total, evidenciando forte estrutura oligárquica, principalmente no estrato herbáceo. Assim, puderam ser apontadas espécies que caracterizam esta formação, a qual é associada com fatores ambientais que condicionam a composição e abundância florística. A análise de similaridade evidenciou que as restingas do sudeste formam dois blocos florísticos distintos, um ao norte (litoral do Espírito Santo) e outro mais ao sul (litoral do Rio de Janeiro). Foram comuns a todas as restingas analisadas Manilkara subsericea,Pilosocereus arrabidae e Byrsonima sericea, podendo ser consideradas de ampla distribuição na costa sudeste.

This study analyzed the structure and floristic composition of an open scrub restinga at Parque Estadual de Itaúnas, Espírito Santo and verified the similarity between floras of the restinga formations in southeastern Brazil. The line intercept method was applied to sample individuals equal or greater than 50 cm tall. The frequency and an importance value were estimated. The similarity of the flora of the restinga formations in southeastern Brazil was performed using the Sørensen index. We surveyed 42 species in 28 families, being Fabaceae and Bromeliaceae the richest families (four species each). The 10 most important species represented 65.6% of the total importance value, showing a strong oligarchic structure, especially in the herbaceous layer. Thus, we identified some species that characterize this formation, which is associated with environmental factors that constrain floristic composition and abundance. The similarity analysis evidenced two distinct floristic blocks of southeastern restingas, one in the north (the coast of Espírito Santo) and another further to the south (coast of Rio de Janeiro). Some species were common to all analyzed resting formations - Manilkara subsericea, Pilosocereus arrabidae and Byrsonima sericea and may be considered of wide distribution on the southeast coast.