Intergeneric relationships within the tribe Alsineae (Caryophyllaceae) as inferred from nrDNA ITS and cpDNArps16 sequences: A step toward a phylogenetically based generic system

Abstract

AbstractThe tribe Alsineae is a large monophyletic group in the family Caryophyllaceae especially found across Eurasia and the Americas, but with a center of diversity in the Mediterranean region. Several previous molecular phylogenetic studies have focused on the delimitation of genera and tribes of Caryophyllaceae, especially the subfamily Alsinoideae or the tribe Alsineae in a broader sense than now recognized. However, there are still many open questions regarding the subdivision of the tribe and genus delimitation. In the present study, we sampled 191 (148 species) and 149 (125 species) accessions of Alsineae representing almost all (Adenonema and Pseudocerastium were not available to us) recognized genera in the tribe for nuclear DNA internal transcribed spacer (ITS) and plastid marker rps16 sequences, respectively. A combined matrix of 103 species was built for taxa with both sequences available. Maximum parsimony and Bayesian inference analyses retrieved Cerastium and Stellaria (including Myosoton) as the largest monophyletic genera, while other genera were medium‐sized (10–20 spp.) or small (<10 spp.). Our expanded sampling of Pseudostellaria and its relatives suggests a broader circumscription of this genus. Major divergence in morphology, particularly of the seeds, observed in the “Protostellaria”‐clade, allows recognition of some taxonomic changes. A total of 16 genera are recognized in Alsineae including Cerastium, Dichodon, Hartmaniella, Holosteum, Lepyrodiclis, Mesostemma, Moenchia, Nubelaria, Odontostemma, Pseudostellaria, Rabelera, Schizotechium, Shivparvatia, and Stellaria, along with Adenonema and Pseudocerastium that could not be analyzed and are, therefore, kept as distinct genera. A diagnostic key to these genera, as well as notes on their relationships, distribution, and nomenclature, is provided.