Molecular and Morphological Analysis Supports the Separation of Robrichia as a Genus Distinct from Enterolobium (Leguminosae: Caesalpinioideae: Mimosoid Clade).
Resource type
Journal article
Date published
March 21, 2022
Abstract
As currently circumscribed, the legume genus comprises 11 species in two sections: sect. and sect. , with an overall distribution from Mexico to Argentina and a centre of diversity in Amazonia. In the absence of the characteristic indehiscent fruits, is difficult to distinguish from other genera in the ingoid clade, including sensu lato, , and . Previous phylogenetic studies which have included have sampled few species of the genus, leaving questions about its monophyly and interspecific relationships. Here we evaluate the circumscription of and its two infrageneric taxa, their phylogenetic placement in the ingoid clade, and interspecific relationships within the two sections of the genus. Our study includes all species, and analyses of nuclear (ITS and ETS) and plastid ( and ) molecular regions, and morphology. Bayesian inference, maximum parsimony, and maximum likelihood analyses show that , as presently circumscribed, is not monophyletic. The genus is divided into two well-supported independent clades, corresponding to the two previously recognized sections; one of them is sister to the genus and is here raised to generic rank as the genus , with three species, , and . The genus consequently now comprises eight species and is more closely related to a clade composed of and . This new arrangement is reinforced by morphological synapomorphies recovered by ancestral character state reconstructions. Indumentum type, the number of pinnae pairs per bipinnate leaf and leaflet pairs per pinna, inflorescence type, and fruit shape characterize , while the recognition of remains based on fruit traits. We also provide the formal lectotypifications for , , , , , and .
Journal title
Systematic Botany
Volume
47
Issue
1
Publisher
American Society of Plant Taxonomists
Place of publication
US
ISSN
0363-6445
eISSN
1548-2324
Official URL
Rights statement
In Copyright