Leaf morphology and venation of Psidium species from the Brazilian Savanna

Abstract

ABSTRACT The Brazilian Savanna biome has the largest plant diversity among savannas worldwide and is the predominant biome in Goiás state, Brazil. Among plant species previously catalogued in the Brazilian Savanna, the Myrtaceae family has received attention, as these plants show great economic potential for its medicinal properties, food and ecological importance, highlighting in this context the Psidium genus. In order to contribute to the differentiation of problematic taxonomic groups, such as Myrtaceae, and to quality control of its plant material, morphological and venation leaf studies of four species of Psidium were performed. For this purpose, leaf samples of Psidium firmum O.Berg., P. myrsinites DC., P. laruotteanum Cambes., and P. guineense Sw. were collected from Goiás State University, Anápolis Air Base, and Serra de Caldas Novas State Park and submitted to classical techniques for morphological and leaf venation characterizations. The results showed that P. firmum presents brochidodromous secondary veins, marginal last venation of the fimbrial type, an abaxial surface with a grooved midrib, flat secondary veins on both sides, an apex obtuse to mucronate, and a rounded base. P. guineense presents trichomes on both surfaces, a grooved midrib on the adaxial surface and a prominent midrib on the abaxial surface, which distinguishes this species from all other Myrtaceae species examined in the present study. The species P. guineense and P. firmum presented a set of differential leaf characteristics among the others taxa of the genus, clearly separating these plants in the morphological identification key.