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Ptilotus R.Br. (Amaranthaceae) is a widespread and species-rich Australian genus. One of the most common arid species, Ptilotus gaudichaudii (Steud.) J.M.Black (paper foxtail), currently comprises the following three subspecies: subsp. gaudichaudii, subsp. eremita (S.Moore) Lally and subsp. parviflorus (Benth.) Lally. In the present study, we re-evaluate the morphological basis for the recognition and status of infraspecies in P. gaudichaudii. Evidence from herbarium and field observations supports the reinstatement of Ptilotus gaudichaudii subsp. eremita and subsp. parviflorus to the rank of species as P. eremita (S.Moore) T.Hammer & R.W.Davis and P. modestus T.Hammer respectively.
Fossil leaves from lowermost Eocene strata in the Otaio River, South Island, New Zealand, include the oldest records of the extant monocot genus, Ripogonum (Ripogonaceae). The Ripogonum fossil is represented by an incomplete leaf with preserved cuticle and is similar to, but different from, all extant and fossil Ripogonaceae, including recently described Eocene Tasmanian and South American taxa and is here described as a new species, R. palaeozeylandiae Conran, E.M.Kenn. & Bannister. This supports the theory that Ripogonaceae have a long and evolutionary history across the southern hemisphere, with the Otaio fossil flora indicating a palaeoclimate similar to the mesothermal broadleaf forests that Ripogonum still occupies today.
This study presents a phylogeny of Zieria Sm. (Rutaceae) based on sequences of internal transcribed spacer and external transcribed spacer regions of nrDNA, and using Neobyrnesia suberosa J.A.Armstr. as the outgroup. The phylogeny includes 109 samples, representing 58 of the 60 currently recognised species of Zieria, with multiple accessions of most. Ten species were resolved as monophyletic on the basis of two, or in one case four, samples. Monophyly of four species was neither supported nor rejected, and all other species with more than one accession were resolved as polyphyletic or paraphyletic. Results showed that divergent paralogues of nrDNA are present in some individuals, although the underlying evolutionary process that gave rise to those paralogues is uncertain. Divergent paralogues within genomes could predate speciation and be variably retained or variably detected within the species sampled here; alternatively, they could represent novel nrDNA combinations formed through hybridisation after speciation. There was no strong evidence for recombination between paralogues or that paralogues represent pseudogenes. Variation of nrDNA sequences was clearly incongruent with previously published cpDNA variation, with the nrDNA potentially providing a better indication of species relationships in Zieria. Evidence for this comes from the greater level of congruence, in some species at least, between nrDNA and existing species-level taxonomy than between cpDNA and taxonomy. Incomplete lineage sorting is proposed as a plausible cause for much of the conflict between nrDNA and cpDNA in Zieria, although, in most cases, there was insufficient information to identify the underlying causes with confidence. Implications for species-level taxonomy are discussed.
A taxonomic revision of southern hemisphere bracteate-prostrate forget-me-nots (Myosotis L., Boraginaceae) is presented here. The group comprises mostly species endemic to New Zealand plus the South American Myosotis antarctica Hook.f. (also Campbell Island) and M. albiflora Hook.f. The statistical analyses of morphological data from herbarium specimens reported here support recognition of five main subgroups on the basis of habit. Excluding the M. pygmaea Colenso species group (M. antarctica, M. brevis de Lange & Barkla, M. drucei (L.B.Moore) de Lange & Barkla, M. glauca (G.Simpson & J.S.Thomson) de Lange & Barkla, and M. pygmaea), which is being treated elsewhere, 14 species are recognised in the following four remaining subgroups: (1) creeping-species group: M. matthewsii L.B.Moore, M. chaffeyorum Lehnebach, M. spatulata G.Forst., M. tenericaulis Petrie, and M. albiflora; (2) cushion-species group: M. uniflora Hook.f., M. pulvinaris Hook.f., and M. glabrescens L.B.Moore; (3) M. cheesemanii M. colensoi species group: M. cheesemanii Petrie and M. colensoi J.F.Macbr.; and (4) M. lyallii species group: M. lyallii Hook.f. and new species M. retrorsa Meudt, Prebble & Hindmarsh-Walls. New species Myosotis umbrosa Meudt, Prebble & Thorsen and M. bryonoma Meudt, Prebble & Thorsen do not fit comfortably within these subgroups. Myosotis elderi L.B.Moore is treated as M. lyallii subsp. elderi (L.B.Moore) Meudt & Prebble. For each of the 14 species revised here, a key to species, descriptions, phenology, distributions, maps, illustrations, specimens examined and notes are provided. Some specimens examined do not fit within these species and require additional comparative studies, including with certain ebracteate-erect species, before taxonomic decisions can be made. Future research on these and other southern hemisphere Myosotis should incorporate the morphological data presented here, with additional genetic, cytological, pollen, and other data in an integrative systematic framework.
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