Poster

         Systematics

Delimitation and Distribution of Magnolia sect. Talauma in Brazil

Presenting Author
Juliana Barbosa
Description
Magnolia L. belongs to the subfamily Magnolioideae (Magnoliaceae), along with Liriodendron L. The family has a curious biogeographical pattern, where 40-50% of the species are native to the Americas, and the rest to Asia; some now extinct species of Magnolia were native to Europe. Magnoliaceae comprises two subfamilies Liriodendroideae Y.W.Law and Magnolioideae Y.W.Law, which are monophyletic and widely recognized. Since the establishment of Magnoliaceae by Jussieu (1789), the taxonomy of the family has attracted the attention of botanists all over the world, mainly in relation to the delimitation of genera and/or sections within the subfamily Magnolioideae, where the genus studied here is included. Regarding the infrageneric classification, Magnolia is divided into three subgenera, subgen. Yulania, subgen. Gynopodium and subgen. Magnolia, where the Talauma section is located, a section that represents the native individuals of Brazil. The species of Magnolia sect. Talauma can be recognized by two parallel longitudinal scars on the petiole caused by the fall of the stipule, in addition to having a woody syncarpus, which breaks into irregular plaques in the dehiscence. Previously, the genus Magnolia was recognized for containing only two species native to Brazil, M. amazonica and M.ovata. The objective of this work was to carry out, for the first time, a morphological and taxonomic study for the genus, seeking to carry out a more accurate morphological delimitation for Brazil. Based on about 350 specimens, we present a more restricted delimitation and a general reorganization in the genus of Magnolia for the country, which resulted in five species (M.amazonica, M.brasiliensis, M. irwiniana, M.ovata and M.sellowiana ). To help in one more factor of differentiation of the species, morphometric analyzes were performed. The use of integrative taxonomy, using taxonomic knowledge in conjunction with morphometric analyzes proved to be effective for the delimitation of species. In addition, we carried out a previous analysis of the conservation status of the species, which showed us an alert about the risk of extinction that most of the studied species present.