Morphometric approach to address taxonomic problems: The case of Utricularia sect. Foliosa (Lentibulariaceae)

Utricularia sect. Foliosa Kamiénski comprises three recognized species, U. amethystina Salzm. ex A.St.‐Hil. & Girard, U. tricolor A.St.‐Hil., and U. tridentata Sylvén, delimited based mainly on shape and structure of the corolla. In comparison with the two latter members of the section, U. amethystina forms a complex of morphological variants, reflected taxonomically by the previous recognition of 31 synonyms. In his monograph of the genus, Taylor synonymized these taxa based primarily on his observation of continuous morphological variation of the flowers. In the same treatment he also suggested a future taxonomic re‐evaluation could re‐establish two, three or more taxa. Here we examine this question utilizing morphometric analyses of floral variation across most of the synonyms mentioned above, within populations from across their Neotropical distribution. Based on both morphological and geographic characters we identify strongly differentiated morphotypes. Our data provide support for both the maintenance of taxa previously recognised as synonyms under U. amethystina, and the resurrection of taxa to species status, namely U. bicolor, U. damazioi, U. lindmanii and U. hirtella, and four other putative new taxa.