Phylogenetics and evolution of phyllotaxy in the S olomon's seal genus P olygonatum ( A sparagaceae: P olygonateae)

P olygonatum is the largest and most complex genus in tribe P olygonateae, comprising approximately 57 species widely distributed in the warm temperate, subtropical and boreal zones of the N orthern H emisphere. However, phylogenetic relationships in the genus remain poorly understood. The objectives of this study were to reconstruct the phylogenetic relationships of the genus using four plastid markers, and to examine the evolution of leaf arrangement in P olygonatum in the phylogenetic context of its closely related taxa. Thirty P olygonatum species were sampled to infer phylogenetic relationships using maximum‐likelihood and B ayesian analyses. The evolution of leaf arrangements was reconstructed using B ayesian, parsimony and likelihood methods. The phylogenetic analyses supported the current generic delimitation of P olygonatum , with H eteropolygonatum recognized as a distinct genus. Three major lineages in P olygonatum were well supported, largely correlated with geographical distribution and the most recent classification at the sectional level. However, our results did not support the currently recognized series, especially the two large series V erticillata and A lternifolia.   B ayesian analyses support the alternate‐leaf arrangement as the ancestral state for P olygonatum , but parsimony and maximum‐likelihood analyses suggest an equivocal state for crown P olygonatum . Leaf arrangement was found to be evolutionarily labile. A new nomenclatural combination was made: Polygonatum sectionSibirica ( L . I . A bramova) Y . M eng, comb. nov.  © 2014 The Linnean Society of London, Botanical Journal of the Linnean Society , 2014, 176 , 435–451.