title: Snowdrops falling slowly into place: an improved phylogeny for Galanthus (Amaryllidaceae).
abstract: Snowdrops (Galanthus, 20 spp.; Amaryllidaceae) are cherished garden plants and the world's most traded wild-sourced ornamental bulb genus. Despite their popularity and economic importance, species delimitation is problematic and the infrageneric classification uncertain. We present a molecular phylogenetic study of Galanthus with the aim of resolving these issues and to better understand the evolution within the genus. Sequences of nuclear encoded nrITS, and plastid encoded matK, trnLF, ndhF, and psbK-psbI, for all currently recognised species and two naturally occurring putative hybrids, were analysed using maximum parsimony and Bayesian inference. Phylogenetic analysis of Galanthus, based on nuclear ITS sequences, provides a well-resolved topology, including seven well-supported named clades (platyphyllus, trojanus, ikariae, elwesii, nivalis, woronowii, and alpinus), and five major clades (A-E). The recovered ITS topology is in accordance with the geographical distribution of Galanthus species. The combined plastid data set provided far less resolution than that of ITS, with generally lower levels of statistical support, and one case of significant incongruence with the ITS dataset (involving G. gracilis). Phylogenetic network and hybridization analyses identified several possible hybridization events but these are more likely to be due to the result of a lack of resolution in the plastid dataset. The putative natural hybrid, G. ×valentinei nothosubsp. subplicatus, is supported by our data and analyses, whereas a hybrid origin for G. ×allenii is not. ITS and plastid data indicated that some Galanthus species are in need of taxonomic recircumscription.
authors.affiliation: The Natural History Museum of Denmark, Sølvgade 83, DK-1307 Copenhagen, Denmark.
authors.forename: Nina
authors.initials: N
authors.lastname: Rønsted
authors.forename: Dimitri
authors.initials: D
authors.lastname: Zubov
authors.forename: Sam
authors.initials: S
authors.lastname: Bruun-Lund
authors.forename: Aaron P
authors.initials: AP
authors.lastname: Davis
mesh_terms: D001499:Bayes Theorem; D005075:Biological Evolution; D002467:Cell Nucleus / Q000235:genetics*; D018744:DNA, Plant / Q000145:classification* / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000145:classification* / Q000235:genetics; D005060:Europe; D027801:Galanthus / Q000145:classification* / Q000235:genetics; D006824:Hybridization, Genetic; D008957:Models, Genetic; D010802:Phylogeny; D058974:Phylogeography; D063148:Plant Dispersal; D018087:Plastids / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: D018744:DNA, Plant; D021903:DNA, Ribosomal Spacer
keywords: Hybridization; ITS; Incongruence; Phylogenetic network; Plastid DNA; Reticulate evolution; Speciation