Reestablishment of the genus Sampaiella J.C. Gomes (Bignoniaceae)

Bignonia trichoclada DC. was originally described from flowering material, later being transferred to Arrabidaea as Arrabidaea trichoclada (DC.) Bureau & K. Schum. Gomes placed it in a monotypic genus Sampaiella, on account of its tomentose indumentum of branched hair and reticulate pollen grains. Sandwith placed Sampaiella in synonymy of Arrabidaea, the fruit of Sampaiella at that time being still unknown. The recent discovery of fruiting material enable the authors to distinguish Sampaiella from Arrabidaea on the basis of fruit and pollen characters. Sampaiella has a linear-oblong capsule with three inconspicuous ribs and a winged margin, quite distinct from the fruit type of Arrabidaea. The pollen is reticulate in Sampaiella, and is different from the microreticulate pollen found in Arrabidaea. These characters support the reestablishment of the genus Sampaiella J.C. Gomes, but leave unanswered its true relationships, which can hopefully be resolved by molecular studies. Bignonia trichoclada DC. foi descrita a partir de material florífero e posteriormente foi transferida para Arrabidaea trichoclada (DC.) Bureau & K. Schum. Gomes posicionou-a no gênero monotípico Sampaiella especialmente pelo indumento tomentoso com tricomas dendríticos e grãos de pólen reticulados. Sandwith sinonimizou Sampaiella em Arrabidaea, mesmo desconhecendo os frutos. A recente descoberta de material frutífero permitiu caracterizar a espécie como tendo cápsula linear-oblonga, com três costelas inconspícuas e margem com alas, bastante distinta da cápsula de Arrabidaea. Os grãos de pólen de Sampaiella apresentam escultura reticulada, diferente da escultura microrreticulada de Arrabidaea. Devido a essas características diferenciais, é proposto o restabelecimento de Sampaiella J.C. Gomes, mas ainda deixa sem resposta seu verdadeiro relacionamento, que provavelmente poderá ser resolvido por estudos moleculares.