Pseudognaphalium (Asteraceae, Gnaphalieae) diversity in New Zealand revealed by DNA sequences with notes on the phylogenetic relationships of Hawaiian Islands plants referred to Pseudognaphalium sandwicensium

ABSTRACT

Pseudognaphalium luteoalbum (L.) Hilliard & Burtt is a morphologically variable cosmopolitan species allied to a number of geographically restricted taxa with a confusing taxonomic history. The relationships and circumscription of these taxa have never been the subject of a global study. We subjected plastid genome and nuclear-ribosomal DNA sequences from New Zealand samples of P. luteoalbum and the threatened endemic P. ephemerum de Lange to phylogenetic analyses along with sequences from elsewhere in the world. Our analyses suggest that two lineages of the genus are present in New Zealand. One was collected from urban and peri-urban locations and we propose it is naturalised to New Zealand. The other was collected from peri-urban and relatively unmodified locations and we propose that it is indigenous and provide the new combination P. lanatum (G.Forst) Smissen, Breitw. & de Lange for the indigenous lineage at species rank. Pseudognaphalium ephemerum sequences were part of the lineage putatively indigenous to New Zealand but their sequences were not distinguishable from some others of this lineage in our analyses. Hawaiian Islands samples attributed to the four varieties of P. sandwicensium (Gaudich) Anderb. may all belong to different species. Sequences of two P. sandwicensium plants match those of the lineage putatively naturalised in New Zealand. Those of P. sandwicensium var. kilaueanum (O.Deg. & Sherff) W.L.Wagner are most similar to those of the putatively indigenous New Zealand lineage. Another group of Hawaiian Islands plants, including one of P. sandwicensium var. molokaiense (O.Deg. & Sherff) W.L.Wagner from west Maui, are more closely related to the Asiatic species P. affine (D.Don) Anderb. than to the other Hawaiian Islands lineages or either New Zealand lineage. The affinities of P. sandwicensium var. hawaiiense (O.Deg. & Sherff) W.L.Wagner lie with native North American Pseudognaphalium species.

KEYWORDS:

• Compositae
• Gnaphalium lanatum
• Hawaiian Islands flora
• New Zealand flora
• Illumina sequencing
• plastid genome
• Pseudognaphalium lanatum
• Pseudognaphalium ephemerum

Acknowledgements

The authors thank Mercè Galbany-Casals for sending us samples of Pseudognaphalium luteoalbum from Portugal and Spain; and AK, BISH, US and WELT (Bridget Hatton) for loans and permission to destructively sample specimens. Manaaki Whenua – Landcare Research (MWLR) GEM lab technical staff and Kèvin Maurin (Waikato University) assisted with parts of the laboratory work. Kerry Ford (MWLR) made collections from the type locality of P. ephemerum. Illumina sequencing was carried out by Otago Genomics Facility and Massey Genome Services. Claudia Lange (MWLR) provided advice on sequence trimming and assembly. We thank Alexander Sennikov (University of Helsinki) for advice on plant nomenclature. Jessie Prebble (MWLR) and Warren Wagner (Smithsonian Institution) provided constructive reviews of a draft and Ray Prebble (MWLR) provided editing. Four anonymous reviewers provided constructive criticism and valuable corrections.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the New Zealand Ministry for Business, Innovation and Employment’s Strategic Science Investment Fund.