Phylogenetic relationships of Australian Poa (Poaceae: Poinae), including molecular evidence for two new genera, Saxipoa and Sylvipoa
Lynn J. Gillespie A D , Robert J. Soreng B and Surrey W. L. Jacobs† CA Research Division, Canadian Museum of Nature, PO Box 3443, Station D, Ottawa, Ontario K1P 6P4, Canada.
B Department of Botany, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013-7012, Australia.
C National Herbarium, Royal Botanic Gardens, Sydney, NSW 2000, Australia.
D Corresponding author. Email: lgillespie@mus-nature.ca
Australian Systematic Botany 22(6) 413-436 https://doi.org/10.1071/SB09016
Submitted: 21 April 2009 Accepted: 21 September 2009 Published: 21 December 2009
Abstract
Phylogenetic relationships among Australian species of Poa and other subtribe Poinae genera were studied on the basis of plastid trnT–trnL–trnF and nuclear ribosomal ITS and ETS DNA sequence data. Molecular evidence is provided for two new monotypic endemic Australian genera, Sylvipoa and Saxipoa, on the basis of two species formerly included in Poa, P. queenslandica and P. saxicola, respectively. Both new genera resolved in a clade with three subtribe Poinae genera, the Australian genus Hookerochloa, the South American genus Nicoraepoa, and the arctic genus Arctagrostis. Sylvipoa and Nicoraepoa are sister taxa. Saxipoa resolved as sister to these plus Arctagrostis, but also shares DNA sequence characters with Hookerochloa, suggesting a possible hybrid origin. All other Australian Poa species studied resolved in a subclade within the P. subgenus Poa supersection Homalopoa clade, supporting their classification together in an expanded P. section Brizoides. Five New Zealand and one New Guinea species also resolved in this subclade, supporting their membership in this section. We postulate a minimum of two dispersal events into Australia, one for Poa and one for other Poinae genera, and a minimum of three into New Zealand and two into New Guinea for Poa.
Acknowledgements
We gratefully acknowledge the support and assistance in the field in Australia from Bryan Simon and Paul Peterson, and the following people and institutions for contribution of samples: Susan Aiken, Annie Archambault, Christian Brochmann, Pilar Catalán, Daniel Stančík, Françiose Hennion (French Polar Institute (IPEV) Program no. 136, headed by Marc Lebouvier), Kelvin Lloyd, Terry Macfarlane, Marina Olonova, Paul Peterson, Sierra Stoneberg-Holt, Neville Walsh, Jun Wen, Stoney Wright, and the USDA Plant Introduction Station of Pullman Washington; Richard Gardner, Jeanette Keeling, Peter de Lange, Shane Wright and Ewen Cameron at the University of Auckland (A New Zealand biodiversity database, unpubl.) are acknowledged for their ITS sequences of New Zealand species and voucher information. We thank Michel Paradis and Roger Bull for assistance in sequencing and laboratory support at the Canadian Museum of Nature; and Jeff Saarela for his helpful review of the manuscript. The Canadian Museum of Nature is acknowledged for financial assistance and support of L. J. G., and the Smithsonian Institution for their continued support of R. J. S.
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† †Deceased.