Revisão taxonômica de Gaya Kunth (Malvoideae, Malvaceae) no Brasil

Abstract

-(Taxonomic revision of Gaya Kunth (Malvoideae, Malvaceae) in Brazil). Gaya comprises 39 Neotropical species with the greatest diversity in Brazil and Peru. Fourteen species occur throughout Brazil, eight of these are endemic, predominantly distributed in the Northeastern region, in Caatinga domain. The genus is characterized by having pendulous flower buds and erect flowers at anthesis, inflated and pendulous schizocarpic fruits (erect at maturity), and mericarps with or without an internal structure (the endoglossum, which can hold the seed), in addition to a constriction on dorsal side or on basal portion and dehiscence on the dorsal face toward the constriction, two characters explored for the first time. This study was based on morphological analyses of approximately 450 herbarium specimens. The taxonomy of the species was based on characters found mainly in fruit and flower, with new diagnostics characters detected. This work includes an analytical key, morphological descriptions, new illustrations, comments about the variability, taxonomic relationship and distribution, maps, new occurrences and conservation data. Keywords: distribution, diversity, morphology, new occurrences RESUMO -(Revisão taxonômica de Gaya Kunth (Malvoideae, Malvaceae) no Brasil). Gaya inclui 39 espécies distribuídas na região Neotropical, com maior diversidade no Brasil e no Peru. No Brasil foram registradas 14 espécies, sendo oito endêmicas, predominantemente na região Nordeste, no domínio da Caatinga. O gênero caracteriza-se pelas flores pêndulas no botão e eretas na antese, pelo esquizocarpo inflado, pêndulo a ereto na maturidade, com mericarpos apresentando ou não uma estrutura interna, a endoglossa, que pode reter a semente, além de uma constrição no lado ventral ou na porção basal e deiscência por todo o lado dorsal até a constrição, sendo que estes dois últimos caracteres foram explorados pela primeira vez. Este estudo foi baseado na análise morfológica de cerca de 450 materiais de herbário. A taxonomia das espécies foi baseada sobretudo nos caracteres do fruto e da flor, com a detecção de novos caracteres diagnósticos. O trabalho consta de chave analítica, descrições morfológicas, ilustrações inéditas, comentários sobre variabilidade e relações taxonômicas, mapas e distribuição geográfica, novas ocorrências e dados de conservação. Palavras-chave: distribuição, diversidade, morfologia, novas ocorrências 1. Parte da Tese de Doutorado da primeira Autora 2.

Fruits of neotropical species of the tribe Malveae (Malvoideae - Malvaceae): macro- and micromorphology

“…The presence or absence of this structure and its size, as well as the arrangement of the seeds in the mericarp, define genera in Malveae (Bovini & Baumgratz 2016). In Gaya gaudichaudiana, for example, the endoglossum is prominent, according to the descriptions of Takeuchi & Esteves (2017) and Masullo et al (2019), but this structure is vestigial in Gaya guerkeana and G. pilosa, as presented here and according to Takeuchi & Esteves (2017). In Briquetiastrum spicatum, it is reduced (Bovini & Baumgratz 2016).…”

“…When comparing the endoglossum in genera of the alliances sensu Bayer & Kubitzki (2003), we clearly see the variation in size and arrangement of this structure. In the genus Gaya, for example, the endoglossum appears as prominent (Masullo et al 2019), originating from the basal dorsal portion of carpels, diverging from the assessment of this structure by Takeuchi & Esteves (2017), who described it as originating from the ventral portion of the mericarp. In Wissadula, according to Barroso et al (1999), this structure is extremely reduced, being characterized only by a scar.…”