Morphometrics and molecular phylogenetics of Angraecum section Dolabrifolia (Orchidaceae, Angraecinae)

• Published in: Plant systematics and evolution 2016-10, Vol.302 (8), p.1027-1045
• Main Authors: Simo-Droissart, Murielle, Sonké, Bonaventure, Droissart, Vincent, Micheneau, Claire, Lowry, Porter P., Hardy, Olivier J., Plunkett, Gregory M., Stévart, Tariq
• Format: Article
• Language: English
• Subjects: Alcohols; Bayesian analysis; Biodiversity; Biodiversity and Ecology; Biological taxonomies; Biomedical and Life Sciences; Botanics; Calyx; Ecology, environment; Ecosystems; Environmental Sciences; Flowers; Genetic variability; Life Sciences; Molecular phylogenetics; Morphology; Morphometry; Original Article; Pectinaria; Phylogenetics; Phylogeny; Plant Anatomy/Development; Plant Ecology; Plant morphology; Plant Sciences; Plant Systematics/Taxonomy/Biogeography; Plastids; Puns; Species; Specimens; Systematics, Phylogenetics and taxonomy; Taxa; Taxonomic revision; Taxonomy; Vegetal Biology
• ISSN: 0378-2697; 1615-6110; 2199-6881
• DOI: 10.1007/s00606-016-1315-5

Species delimitation within Angraecum section Dolabrifolia is problematic due to morphological variability coupled with overlap in many of the characters traditionally used to distinguish species. Recent molecular phylogenetic studies of the genus included three of the five currently described species of the Dolabrifolia group, placing them as sister to continental African species of Angraecum sect. Pectinaria. In preparation for a taxonomic revision of section Dolabrifolia, we analyzed morphological and molecular data to re-assess the circumscription of each of the five currently described species, examined the relationships among members of the section, and assessed their position within the genus. We used 172 alcohol-preserved specimens to perform multi variate analyses on 15 morphological characters. We also collected molecular sequence data from 16 taxa including all members of the section using six DNA regions, and analyzed these data with parsimony and Bayesian methods. The morphometric study revealed five distinct groups, of which four correspond to currently recognized species, while the fifth represents a taxonomic novelty. Angraecum podochiloides is the most distinctive morphologically, recognizable by its narrow leaves bearing white-yellowish flowers. The often confused species Angraecum distichum and Angraecum bancoense are clearly distinguishable by flower size. Molecular phylogenetic analyses indicated that section Dolabrifolia forms a well-supported clade related to the continental African members of section Pectinaria. Four species are well delimited, while the accessions of Angraecum aporoides formed two well-supported clades corresponding to two subclusters revealed by the morphometric study. The recently published Angraecum poppendickianum is shown to be a synonym of A. distichum.