This paper introduces a special issue of Nuytsia containing seven collaborative papers naming 50 new species of Western Australian vascular plants. It has been compiled to celebrate the 50th anniversary of the opening of the Western Australian Botanic Garden at Kings Park. Several species are named after former Kings Park staff to honour their contributions to botany in Western Australia, including one that occurs naturally in the Kings Park bushland and is named after one of the designers of the Botanic Garden. Field research by Kings Park staff across Western Australia, including the rediscovery of Auranticarpa resinosa (Domin) L.W.Cayzer, Crisp & I.Telford, missing for 180 years, is documented.
Twenty-seven new species of vascular plants from Western Australia
BARRETT, R.L. AND BARRETT, M.D., Nuytsia26: 21–87 (2015)
Twenty-seven new species are described from Western Australia. Bossiaea arenitensis R.L.Barrett, B. zarae R.L.Barrett (Fabaceae), Commelina roensis M.D.Barrett & R.L.Barrett (Commelinaceae), Crinum joesmithii M.D.Barrett & R.L.Barrett (Amaryllidaceae), Eriocaulon rivicola G.J.Leach, M.D.Barrett & R.L.Barrett (Eriocaulaceae), Glycine remota M.D.Barrett & R.L.Barrett (Fabaceae), Hybanthus bennettiae R.L.Barrett (Violaceae), Mitrasacme thedae M.D.Barrett & R.L.Barrett (Loganiaceae), Nymphoides astoniae M.D.Barrett & R.L.Barrett (Menyanthaceae), Proiphys kimberleyensis M.D.Barrett & R.L.Barrett (Amaryllidaceae), Schoenus thedae M.D.Barrett & R.L.Barrett (Cyperaceae), Trachymene pavimentum M.D.Barrett & R.L.Barrett (Araliaceae), Tribulopis marliesiae R.L.Barrett (Zygophyllaceae), Triodia celsa M.D.Barrett and T. diantha M.D.Barrett (Poaceae) are described from the Kimberley region. Aphyllodium beardii R.L.Barrett (Fabaceae) is described from the Great Sandy Desert and Triodia basitricha M.D.Barrett is described from the Pilbara region. Calectasia demarzii R.L.Barrett, C. elegans R.L.Barrett, C. jubilaea R.L.Barrett, C. valida R.L.Barrett (Dasypogonaceae), Caustis deserti R.L.Barrett, C. gigas Meney & K.W.Dixon ex R.L.Barrett, Lepidosperma fairallianum R.L.Barrett, L. hopperi R.L.Barrett, L. oldhamii R.L.Barrett (Cyperaceae) and Poranthera asybosca R.L.Barrett (Phyllanthaceae) are described from the south-west of Western Australia. All new species are illustrated and their conservation status assessed.
Four new species of Boronia (Rutaceae) from the Kimberley region of Western Australia
BARRETT, R.L.,BARRETT, M.D. AND DURETTO, M.F., Nuytsia26: 89–109 (2015)
Four new species of Boronia Sm. are described from the North Kimberley region of Western Australia: B. cremnophila R.L.Barrett, M.D.Barrett & Duretto, B. interrex R.L.Barrett, M.D.Barrett & Duretto, B. marcoana R.L.Barrett & M.D.Barrett and B. thedae R.L.Barrett, M.D.Barrett & Duretto. All of these species have very restricted distributions and are of conservation concern. All new species are illustrated. A revised key to Boronia species in the Kimberley region is provided.
Seven new species of Haemodorum (Haemodoraceae) from the Kimberley region of Western Australia
BARRETT, R.L.,HOPPER, STEPHEN D.,MACFARLANE, T.D. AND BARRETT, M.D., Nuytsia26: 111–125 (2015)
Haemodorum basalticum R.L.Barrett, Hopper & T.Macfarlane, H. capitatum R.L.Barrett & Hopper, H. condensatum Hopper & R.L.Barrett, H. griseofuscum R.L.Barrett, M.D.Barrett & Hopper, H. interrex R.L.Barrett & M.D.Barrett, H. macfarlanei R.L.Barrett and H. thedae R.L.Barrett are described as new species. Haemodorum basalticum and H. macfarlanei are restricted to the Mitchell Plateau, H. capitatum is restricted to pindan sands in the Dampier Botanical District, H. condensatum is known from a small area in the remote Prince Regent National Park, H. griseofuscum is only known from a single location on Doongan Station in Western Australia, although possibly also occurs in the Northern Territory, H. interrex is restricted to the area around the headwaters of the Prince Regent River, and H. thedae is only known from Theda Station. A key is presented to all species known to occur in the Kimberley region, and H. subvirens F.Muell. and H. coccineum R.Br. are newly recorded for the region.
Four new species of Stylidium (Stylidiaceae) from the Kimberley region of Western Australia
BARRETT, R.L.,BARRETT, M.D.,KENNEALLY, K.F. AND LOWRIE, A., Nuytsia26: 127–141 (2015)
Stylidium latrodectus R.L.Barrett, M.D.Barrett & Lowrie, S. pindanicum R.L.Barrett, S. saintpaulioides R.L.Barrett, M.D.Barrett & Lowrie and S. willingii R.L.Barrett, Kenneally & Lowrie are described as new species from the Kimberley region of Western Australia. All species are illustrated and modified keys are presented.
A new species of Gomphrena (Amaranthaceae) from the Bonaparte Archipelago, Western Australia
BARRETT, R.L. AND PALMER, J., Nuytsia26: 143–147 (2015)
Gomphrena splendida R.L.Barrett & J.Palmer is described as a new species endemic to islands of the Bonaparte Archipelago in the north-west Kimberley region of Western Australia. This new species has a highly restricted distribution. It is unusual among the Australian species of Gomphrena L. in being a large, fleshy, perennial with very large flowers, giving this species significant horticultural potential in tropical areas. A modified key and images are presented.
Two new species of Phyllanthus from northern Australia and notes on Phyllanthus, Sauropus and Synostemon (Phyllanthaceae) in Western Australia
BARRETT, R.L. AND TELFORD, I.R.H., Nuytsia26: 149–166 (2015)
Two new species of Phyllanthus L. are described, both included within P. subgen. Lysiandra F.Muell.; P. eremicus R.L.Barrett & I.Telford occurring in the Pilbara, Great Sandy Desert and southern Dampierland bioregions of Western Australia and the Tanami region of the Northern Territory, and P. hamelinii I.Telford & R.L.Barrett restricted to the Carnarvon bioregion, Western Australia. Both species have reasonably restricted or poorly known distributions and P. eremicus is of some conservation concern. Sauropus rigidulus (Müll.Arg.) Airy Shaw is formally recorded for Western Australia and a full description is provided. All of these taxa have previously been listed on Western Australia.s plant name census as phrase-named taxa. All three species are described and illustrated. Notes are made on the application of misapplied names and phrase-named taxa in Phyllanthus, Sauropus Blume and Synostemon F.Muell. in use in Western Australia.
Five new species and a new combination in Cyperaceae from the Kimberley region of Western Australia
Four new species of Actinoschoenus Benth. and one new species of Fimbristylis Vahl are described from the north Kimberley region of Western Australia: A. glabrispiculus Rye, R.L.Barrett & M.D.Barrett, A. pentagonus Rye, R.L.Barrett & M.D.Barrett, A. quadricostatus Rye, R.L.Barrett & M.D.Barrett, A. ramosus Rye, R.L.Barrett & M.D.Barrett, and F. helicophylla Rye, R.L.Barrett & M.D.Barrett. One new combination is made: A. arthrostyloides (W.Fitzg.) K.L.Clarke, K.L.Wilson & J.J.Bruhl. Several of these species have very restricted distributions and are of conservation concern. Two species also occur in the western Northern Territory. All of these taxa have previously been listed on Western Australia.s plant census under phrase names. All species are illustrated. A revised key to species of Actinoschoenus in the Kimberley region is provided.