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

Abstract

Utricularia sect. Foliosa Kami enski comprises three recognized species, U. amethystina Salzm. ex A.St.-Hil. & Girard, U. tricolor A.St.-Hil., and U. tridentata Sylv en, 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.

Intraspecific Variation within the Utricularia amethystina Species Morphotypes Based on Chloroplast Genomes

“…Our results support that the sampling based on three different morphotypes proved to be insufficient to allow firm conclusions on the U. amethystina species separation, considering we sampled one individual per morphotype. However, the scenario presented here based on chloroplast genomes suggests that U. amethystina morphotypes may be different species as previous studies based on morphometric approach [12] and phylogeny with few loci [13], but with more populations, have suggested.…”

“…This polymorphism resulted in a historically taxonomic complicated group with its systematics only partially resolved to date. During the last decades, several efforts attempted to separate the different U. amethystina morphotypes into different species, yet without much success [7,12,13].…”

“…This intraspecific morphological variation resulted in several taxonomic rearrangements since the earliest descriptions at nineteenth century [10,11] and even now there is much controversy about if the species is one or more [12,13]. Taylor (1989) [7] struggled to separate the species based on reproductive characters, such as corolla shape, pedicel sizes, palynological characters, and calyx indumentum, but he couldn't find traits for enough taxonomical circumscriptions to split the different morphotypes.…”

“…The chloroplast genomes of most angiosperms have conserved quadripartite structure separated in Large and Small Single Copy regions (LSC and SSC, respectively) and two inverted repetitive regions (IRs) [16]. However, comparative analyses indicate that some plants, such as parasitic [17], This intraspecific morphological variation resulted in several taxonomic rearrangements since the earliest descriptions at nineteenth century [10,11] and even now there is much controversy about if the species is one or more [12,13]. Taylor (1989) [7] struggled to separate the species based on reproductive characters, such as corolla shape, pedicel sizes, palynological characters, and calyx indumentum, but he couldn't find traits for enough taxonomical circumscriptions to split the different morphotypes.…”

Lentibulariaceae from Serra dos Pireneus, Goiás, Brazil

“…The corolla usually has a purple color and is scarcely observed in its white form. This natural color polymorphism was already reported by several authors (Taylor 1989;Silva et al 2011;Baleeiro et al 2016). Even so, U. amethystina is distinguished by its curved long spur and its yellow spot at the lower lip.…”