First molecular phylogenetic insights into the evolution of Eriocaulon (Eriocaulaceae, Poales)

Abstract

Eriocaulon is a genus of c. 470 aquatic and wetland species of the monocot plant family Eriocaulaceae. It is widely distributed in Africa, Asia and America, with centres of species richness in the tropics. Most species of Eriocaulon grow in wetlands although some inhabit shallow rivers and streams with an apparent adaptive morphology of elongated submerged stems. In a previous molecular phylogenetic hypothesis, Eriocaulon was recovered as sister of the African endemic genus Mesanthemum . Several regional infrageneric classifications have been proposed for Eriocaulon . This study aims to critically assess the existing infrageneric classifications through phylogenetic reconstruction of infrageneric relationships, based on DNA sequence data of four chloroplast markers and one nuclear marker. There is little congruence between our molecular results and previous morphology-based infrageneric classifications. However, some similarities can be found, including Fyson’s sect. Leucantherae and Zhang’s sect. Apoda . Further phylogenetic studies, particularly focusing on less well sampled regions such as the Neotropics, will help provide a more global overview of the relationships in Eriocaulon and may enable suggesting the first global infrageneric classification. Electronic supplementary material The online version of this article (10.1007/s10265-019-01129-3) contains supplementary material, which is available to authorized users.

Insights into the phylogeny and chloroplast genome evolution of Eriocaulon (Eriocaulaceae)

“…As a famously difficult taxonomic group, effective molecular markers are necessary to rapidly assess genetic divergence and identify species. However, universal or common molecular markers are ineffective for this group [ 4 , 12 ]. The mutation events are not random and are concentrated in hotspot regions in the chloroplast genome sequences, so variable markers or species barcodes can be identified in the chloroplast genome [ 32 , 54 ].…”

“…Mesanthemum is only distributed in Africa, and most Eriocaulon species are confined to tropical and subtropical regions. There are three centers of species diversity, namely Africa (contains 111 species), the Americas (contains 122 species), and Asia (contains 220 species) [ 3 , 4 ].…”

“…Davies et al [ 9 ] resolved the taxonomy of the E. carsonii complex in Australia with amplified fragment length polymorphism (AFLP) genetic markers. Recently, Larridon et al [ 4 ] used five markers, including four chloroplast markers and one nuclear marker, to create the first molecular phylogenetic study for the genus. Darshetkar et al [ 12 ] focused on the Indian Eriocaulon species that 552 accessions from 66 Eriocaulon species were analyzed.…”

Stability Despite Reduction: Flower Structure, Patterns of Receptacle Elongation and Organ Fusion in Eriocaulon (Eriocaulaceae: Poales)

“…Indeed, Kral [45] reported the occurrence of three spreading, peglike, minute appendages on the gynophore, and it is likely that these were petals. In the light of recent molecular phylogenetic data [44], the entire E. cinereum group needs a worldwide taxonomic revision. We highlight an urgent need of use of developmental data documented by scanning electron microscopy to assess variation of floral characters in the group.…”

“…Cook [42] adopted a broad taxonomic concept and placed E. redactum in synonymy of E. cinereum s.l., but subsequent authors highlighted a need of recognizing it as closely related, but distinct species [29,35,43]. A wide species concept of E. cinereum is recently questioned by Larridon et al [44] based on a global molecular phylogenetic study of Eriocaulon. Obviously, a taxonomic revision of the entire E. cinereum complex is needed, but it is out of the scope of the present study, which is aimed in resolving issues of flower structure and development.…”