Revision of generic concepts in Schoeneae subtribe Tricostulariinae (Cyperaceae) with a new Australian genus Ammothryon and new species of Tricostularia

<p>The <i>Tricostularia</i> Nees ex Lehm. group of genera is reviewed and formally recognised as Cyperaceae tribe Schoeneae subtribe Tricostulariinae R.L.Barrett, K.L.Wilson & J.J.Bruhl. Molecular data from plastid <i>rbc</i>L and <i>trnL-F</i> and nuclear ITS and ETS regions are combined with a novel assessment of morphological characters to support our new classification. Six genera are included: a new genus, <i>Ammothryon</i> R.L.Barrett, K.L.Wilson & J.J.Bruhl, and the named genera <i>Chaetospora</i> R.Br., <i>Morelotia</i> Gaudich., <i>Tetraria</i> P.Beauv., <i>Tricostularia</i>, and <i>Xyroschoenus</i> Larridon. <i>Ammothryon, Chaetospora</i> and <i>Tricostularia</i> are all endemic to southern Australia. <i>Morelotia</i> has one species each in Hawaii, French Polynesia and New Zealand, and three species in southwest Western Australia. <i>Tetraria</i> has a disjunct distribution in Southern Africa, Borneo, New Guinea and New Caledonia. <i>Xyroschoenus</i> is endemic to the Seychelles. <i>Tetrariopsis</i> C.B.Clarke (based on <i>Tetrariopsis octandra</i> (Nees) C.B.Clarke) is included under an expanded concept of <i>Morelotia</i>, which also includes <i>Tetraria australiensis</i> C.B.Clarke and <i>Tetraria microcarpa</i> S.T.Blake from south-west Western Australia. <i>Tricostularia bennettiana</i> R.L.Barrett & K.L.Wilson, <i>Tricostularia davisii</i> R.L.Barrett & K.L.Wilson, <i>Tricostularia lepschii</i> R.L.Barrett & K.L.Wilson, <i>Tricostularia newbeyi</i> R.L.Barrett & K.L.Wilson, and <i>Tricostularia sandifordiana</i> R.L.Barrett & K.L.Wilson are described as new species from south-west Western Australia. The following new combinations are made: <i>Ammothryon grandiflorum</i> (Nees ex Lehm.) R.L.Barrett, K.L.Wilson & J.J.Bruhl, <i>Morelotia australiensis</i> (C.B.Clarke) R.L.Barrett & K.L.Wilson, <i>Morelotia microcarpa</i> (S.T.Blake) R.L.Barrett & K.L.Wilson, <i>Morelotia octandra</i> (Nees) R.L.Barrett & J.J.Bruhl and <i>Tricostularia drummondii</i> (Steud.) R.L.Barrett & K.L.Wilson. <i>Tricostularia drummondii</i> is reinstated from synonymy (formerly <i>Discopodium drummondii</i> Steud.), having previously been confused with <i>T. exsul</i> (C.B.Clarke) K.L.Wilson & R.L.Barrett. Lectotypes are selected for <i>Chaetospora flexuosa</i> var. <i>gracilis</i> Boeckeler, <i>Discopodium drummondii</i> Steud., <i>Elynanthus grandiflorus</i> Nees ex Lehm., <i>Lampocarya affinis</i> Brongn., <i>Lepidosperma exsul</i> C.B.Clarke, <i>Morelotia gahniiformis</i> Gaudich. var. <i>minor</i> A.Rich., <i>Tetraria australiensis</i> C.B.Clarke, <i>Tetraria capillacea</i> var. <i>intercedens</i> Kük., <i>Tricostularia compressa</i> Nees ex Lehm. and <i>Tricostularia neesii</i> Lehm.</p>