Molecular phylogeny and dating of Asteliaceae (Asparagales): Astelia s.l. evolution provides insight into the Oligocene history of New Zealand

[Display omitted] ► The Asteliaceae phylogeny is reconstructed and divergence dates estimated. ► Astelia is paraphyletic as Collospermum is nested within it, while Milligania and Neoastelia are sister. ► Astelia s.l. diversity and distributions of extant taxa are the result of long-distance dispersal. ► Date estimates for Astelia s.l. evolution inter the presence of Astelia s.l. in New Zealand during the Oligocene. ► Alpine taxa from New Zealand and Australia have recent origins from the Late Miocene onwards. Asteliaceae (4 genera, 36 species) are found on both continents and island archipelagos in the southern hemisphere and across the Pacific. The circumscription of Asteliaceae and intrageneric relationships are poorly understood. We generated a phylogeny including all genera and 99% of the species using DNA sequence data from chloroplast (trnL, psbA–trnH, rps16, and petL–psbE) and nuclear (NIA-i3) regions. Relaxed clock methods were applied to infer the age of the family and the timing of cladogenic events. Generic delimitations change as a result of this study. Collospermum is nested within Astelia and is recognized here only at the subgeneric level. Further, Astelia subgenera Astelia, Asteliopsis, and Tricella are paraphyletic and to achieve monophyly their recircumscriptions are proposed. Despite the presence of Asteliaceae taxa on multiple Gondwanan landmasses and proposed Cretaceous origins for the family, radiation of genera was during the Tertiary. The largest and oldest genus, Astelia s.l. (including Collospermum), radiated around the Eocene/Oligocene boundary (ca. 34.2million years ago (Ma)). Astelia s.l. subgenera diverged from the Oligocene/Miocene boundary onwards (