Phylogeny of the restiid clade (Poales) and implications for the classification of Anarthriaceae, Centrolepidaceae and Australian Restionaceae

Abstract

Three families, Anarthriaceae, Restionaceae and Centrolepidaceae, are generally recognised in the restiid clade of Poales. A new phylogeny is presented, with fuller sampling of Australian taxa, based on analyses of trnL‐F, trnK and rbcL data from the chloroplast genome. The findings agree with the major groups shown in previous molecular studies but provide a more substantial basis for reviewing the classification at family and generic levels. Anarthriaceae is sister to Restionaceae, with Anarthria sister to Lyginia+Hopkinsia. Centrolepidaceae, on an extremely long branch, appears embedded in Restionaceae in Bayesian trees; although it appears as sister to Restionaceae in analyses that are more subject to long‐branch attraction (in parsimony analyses and those of data from the less‐conserved trnL‐F cpDNA region). Accepting the embedded position, which would make this a subfamily of Restionaceae, the basal division in the Restionaceae separates the African subfamily Restionoideae from the Australasian clade (Sporadanthoideae, Centrolepidoideae, Leptocarpoideae). In subfamily Leptocarpoideae, Eurychorda forms the basal branch. At the next dichotomy the Leptocarpus clade, together with the Winifredia clade, is separated from a diverse assemblage including Loxocarya, Chordifex, Baloskion, Desmocladus, Lepidobolus and allied genera. The phylogeny indicates that several currently recognised genera are not monophyletic and that changes to the generic classification are required. A matrix of morphological characters was prepared and these were mapped onto the Bayesian consensus DNA tree to identify synapomorphies of the clades and genera. Observations on leaf laminae indicate that fully or partially unifacial leaf laminae are a synapomorphy of the restiid clade. The morphological characterisation of the following are considered: the restiid clade, Anarthriaceae, Restionaceae enlarged to include subfamily Centrolepidoideae, Leptocarpus s.l. (including as potential synonyms Meeboldina and Stenotalis) and Desmocladus s.l. (including potentially Harperia, Onychosepalum and Kulinia).

Desmocladus (Restionaceae) enlarged to include the Western Australian Harperia, Kulinia and Onychosepalum

“…The Desmocladus clade was recognised by Briggs and Johnson (1999), being named after its first-named and largest genus, and is supported by analyses of chloroplast DNA data (Briggs et al 2010(Briggs et al , 2014. The clade is characterised morphologically by uninterrupted culm chlorenchyma, lacking pillar cells and sclerenchyma 1 This paper is dedicated to my former colleague Elizabeth Anne Brown (1956Brown ( -2013, remembering especially her notable achievements in the study of bryophytes and Ericaceae, her love of fieldwork, and her service for many years as Scientific Editor of Telopea.…”

“…Recently Briggs et al (2014) presented a phylogeny of the restiid clade of Poales that included new data and analyses for the largely Australasian subfamily Leptocarpoideae. The phylogeny indicated that the three small Western Australian genera Kulinia B.G.…”

“…Similar results were also found by Briggs et al (2010) with fewer taxa sampled. The relevant part of a phylogenetic tree from Briggs et al (2014) based on concatenated trnL-F and trnK data from the chloroplast genome is shown in Figure 1. Morphological characteristics do not provide support for the further division of Desmocladus, rather support its expansion to include the smaller genera embedded within it.…”

Leptocarpus (Restionaceae) enlarged to include Meeboldina and Stenotalis, with new Western Australian species and subgenera

“…The phylogeny of Leptocarpoideae presented by Briggs et al (2014) was based on concatenated sequences of trnK and trnL-F with coded indels, analysed by both Bayesian inference and maximum parsimony. Most species are represented by a single sequence for each gene but several are replicated.…”

“…, Briggs and Johnson (1999), Meney et al (1999), Paczkowska and Chapman (2000), Wheeler et al (2002); Meeboldina sp. D, Briggs et al (2014).…”