Phylogenetic relationships of the Australasian shrubby everlastings Ozothamnus and Cassinia (Asteraceae: Asteroideae: Gnaphalieae)

Abstract

The first comprehensive phylogenetic study of the Australasian shrubby everlastings Ozothamnus, Cassinia, and their satellite genera is presented based on the nuclear ribosomal external and internal transcribed spacer and three chloroplast spacer regions (matK‐psbA, psbA‐trnH, ycf6‐pbsM). While the hypothesis of the monophyly of the sequence copies found in Cassinia cannot be rejected, sequences from Ozothamnus are found to be non‐monophyletic in three possible taxonomic circumscriptions of that genus. Cassinia, Calomeria, Odixia and Haeckeria are nested in a narrowly circumscribed Ozothamnus. Ozothamnus section Hebelaena, a sub‐shrubby group long recognized as potentially misplaced in the genus, is more heterogeneous than expected and is found to be potentially polyphyletic. Perhaps more surprisingly, a group of four species previously considered part of “core” Ozothamnus is found to be more closely related to other genera. It includes the subalpine “cascade everlastings” of south‐eastern Australia. Although many characters traditionally used for the delimitation of genera are homoplasious, connivent involucral bracts and presence of paleae are synapomorphies for Cassinia. Except for the robust shrubby habit, no morphological synapomorphy for core Ozothamnus/Cassinia is currently evident. Future studies are needed to test these results with additional data, to identify morphological and anatomical synapomorphies for individual clades and to resolve species‐level relationships with more extensive sampling to address the possibilities of incomplete lineage sorting or reticulate evolution.

Phylogenetic diversity and endemism of Australian daisies (Asteraceae)

“…In the absence of a broadly sampled species‐level phylogeny of the Australian Asteraceae, it is admittedly unclear whether several of the large genera in this study are actually monophyletic, and some are probably not (e.g. Schmidt‐Lebuhn & Constable, ). The same situation will presumably be encountered in other groups on which analyses of phylogenetic diversity are conducted using higher‐level phylogenies.…”

“…Additional sequences were generated to add genera but also to fill in gaps in the dataset for genera already represented (Appendix S1). Extractions, PCR, purification, sequencing and contig-building were conducted as described in Schmidt-Lebuhn & Constable (2013). The matK and trnL-trnF regions were amplified and sequenced in parts using primers 'c', 'd', 'e' and 'f' of Taberlet et al (1991) for matK, and primers 2R and 3914F of Johnson & Soltis (1994) and 1408F and 1541R of Bayer et al (2002) for trnL-trnF.…”

Phylogenetic relationships of Coronidium, Xerochrysum and several neglected Australian species of “Helichrysum” (Asteraceae: Gnaphalieae)

“…Selection of sequence regions. -The nuclear ribosomal external transcribed spacer (ETS), the nuclear ribosomal internal transcribed spacer (ITS), and the chloroplast spacer regions matK-psbA, psbA-trnH and ycf6-psbM (Sang & al., 1997;Shaw & al., 2005) were chosen for the study due to their comparatively high degree of variability in Australasian Gnaphalieae (e.g., Bayer & al., 2002;Smissen & al., 2004Smissen & al., , 2011Schmidt-Lebuhn & Constable, 2013).…”

“…Its results showed the two Xerochrysum as non-monophyletic and grouped with various other representatives of Australian Gnaphalieae but with poor to non-existent branch support for all relevant relationships. Although other phylogenetic studies of Australian Gnaphalieae have been conducted since, they focused on other genera (e.g., Ford & al., 2007;Schmidt-Lebuhn & Constable, 2013).…”

Recent assembly of the global herbaceous flora: evidence from the paper daisies (Asteraceae: Gnaphalieae)

“…Both chloroplast DNA (cpDNA) and nuclear DNA (nrDNA) have been used extensively in Asteraceae phylogenetics, including in the tribe Gnaphalieae (Breitwieser et al ., ; Galbany‐Casals et al ., , ; Bergh & Linder, ; Blöch et al ., ; Schmidt‐Lebuhn & Constable, ). In general, both nrDNA and cpDNA indicate similar phylogenetic results in Gnaphalieae.…”