Delimitation and status of Handroanthus heptaphyllus and H. impetiginosus. (Bignoniaceae, Tecomeae)

Abstract

Two species of the genus Handroanthus with pink (eventually white) flowers are recognized in Argentina: Handroanthus heptaphyllus and H. impetiginosus. Those two species, treated as synonyms by some authors, are closely related by their morphology, and often mis-identified, particularly at juvenile stages. We studied adult and juvenile morphology of both entities to establish both their taxonomic boundaries and status. One hundred herbarium specimens were analyzed, new collections of native and cultivated individuals were made, and some of these were cultivated from seeds, so that young seedlings could also be studied. We found clear morphological differences that support the recognition of two different species. Descriptions, keys and illustrations are provided for both species as adult and seedlings. We also present a table summarizing differences between both species at different developmental stages and a map with their distribution in Argentina.