We present a new worldwide phylogenetic classification of 11 506 grass species in 768 genera, 12 subfamilies, seven supertribes, 52 tribes, five supersubtribes, and 90 subtribes; and compare two phylogenetic classifications of the grass family published in 2015 (Soreng et al. and Kellogg). The subfamilies (in descending order based on the number of species) are Pooideae with 3968 species in 202 genera, 15 tribes, and 30 subtribes; Panicoideae with 3241 species in 247 genera, 13 tribes, and 19 subtribes; Bambusoideae with 1670 species in 125 genera, three tribes, and 15 subtribes; Chloridoideae with 1602 species in 124 genera, five tribes, and 26 subtribes; Aristidoideae with 367 species in three genera, and one tribe; Danthonioideae with 292 species in 19 genera, and one tribe; Micrairoideae with 184 species in eight genera, and three tribes; Oryzoideae with 115 species in 19 genera, four tribes, and two subtribes; Arundinoideae with 40 species in 14 genera, two tribes, and two subtribes; Pharoideae with 12 species in three genera, and one tribe; Puelioideae with 11 species in two genera, and two tribes; and the Anomochlooideae with four species in two genera, and two tribes. We also include a radial tree illustrating the hierarchical relationships among the subtribes, tribes, and subfamilies. Newly described taxa include: supertribes Melicodae and Nardodae; supersubtribes Agrostidodinae, Boutelouodinae, Gouiniodinae, Loliodinae, and Poodinae; and subtribes Echinopogoninae and Ventenatinae.

A re-assessment of members of the family Saxifragaceae in the Canadian Arctic Archipelago is presented as a traditional key and annotated checklist that recognizes 17 taxa. The information on which this paper is based is recorded in a developing DELTA database that aims to collect the following data: place of valid publication; synonymy, usually limited to names that have been associated with the Canadian Arctic; common name(s), if applicable; vegetative and floral morphological characters; data on the distribution, including information about the northernmost record of the taxon; habitat preferences of each species; notes on the species as an environmental indicator; indigenous knowledge; and expanded notes conveying additional information. The database also contains maps, illustrations of characters useful for identification, and colour photographs and line drawings of the taxa. Appendices list characters recorded in the database, brief taxonomic notes, and a sample species description. The data are available on the Internet at http://biodiversity.uno.edu/delta/ as natural-language descriptions and as an INTKEY interactive identification and information-retrieval package for Windows.Résumé : Les auteurs présentent une ré-évaluation des membres de la famille des Saxifragaceae de l'archipelle Arctique Canadien, sous forme d'une clé traditionnelle et d'une liste annotée reconnaissant 17 taxons. L'information sur laquelle ce travail est basé est enregistrée dans une banque de données DELTA, en développement, qui vise à réunir les informations suivantes : localisation de publications valides, synonymie habituellement limitée aux noms qui ont été associés avec l'Arctique Canadien, nom(s) commun(s) si approprié, caractères morphologiques végétatifs et floraux, données sur la distribution, incluant de l'information sur la mention la plus nordique pour le taxon, habitats préférés de chaque espèce, notes sur l'espèce comme indicateur environnemental, connaissance par les indigènes, et un ensemble de notes sur des informations additionnelles. La banque de données comporte également des cartes, des illustrations de caractères utiles pour l'identification, des photographies en couleurs ainsi que des dessins de ces taxons. Les appendices présentent les caractères enregistrés dans la banque de données, de courtes notes taxonomiques et un échantillon de description de l'espèce. Les données sont disponibles par Internet à http://biodiversity.uno.edu/delta/ sous forme de descriptions en langage naturel et sous forme d'un fichier transférable INTKEY pour identification interactive et retrait d'informations sur MS-Windows. Mots clés : Arctique, Canada, DELTA, Internet, Saxifragaceae, taxonomie. [Traduit par la Rédaction] Aiken et al. 2036 Porsild (1957Porsild ( , 1964 and incorporated relevant information published since the latter date. The Poaceae was chosen as the first family to be revised, for reasons that were documented. The DELTA format (Description Language for Tax-Can.

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Tuktut Nogait National Park is located in the Melville Hills in the northeastern corner of mainland Northwest Territories in Canada's Southern Arctic Ecozone. The first major floristic survey of the Melville Hills region was conducted in 1990 as part of a natural resource inventory to determine its suitability as a National Park. We studied the flora and made extensive plant collections in Tuktut Nogait National Park and the Melville Hills region in 2009. Here, we present a comprehensive annotated checklist to the region's vascular plant flora based on a review of all existing and our own new collections. This includes the citation of all specimens examined, colour photographs for a subset of taxa and detailed taxonomic comments. The Melville Hills flora comprises 268 taxa (265 species and three additional infraspecific taxa), a 16% increase from the first survey, 215 of which are known from Tuktut Nogait National Park. Forty-eight taxa are newly recorded for the region and 54 taxa are newly recorded for Tuktut Nogait National Park. Noteworthy records include range extensions for Botrychium lunaria, Carex concinna, Draba borealis, Myriophyllum sibiricum, Plantago eriopoda, Poa alpina, Poa ammophila, Puccinellia banksiensis, Salix arbusculoides, and Selaginella selaginoides. The flora includes 19 vascular plant species of potential conservation concern in the Northwest Territories, including six assessed as "May Be At Risk", of which one occurs in the Park and 13 assessed as "Sensitive", of which eight occur in the Park.

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Poa, the largest genus of grasses (Poaceae) with over 500 species, occurs throughout temperate and boreal regions in both hemispheres. A phylogenetic study of Poa based on trnT-trnF chloroplast DNA sequence data is presented focusing on basal relationships, major clades, generic boundaries, and placement of putatively closely related genera. Results support the monophyly of the main lineage of Poa if subgen. Andinae is excluded and Anthochloa, Austrofestuca, Dissanthelium (at least in part), and Eremopoa are included. The main Poa clade and subgen. Andinae resolve within a strongly supported Poinae-Alopecurinae-Miliinae clade (PAM). The subdivision of Poa into five major clades, proposed based on chloroplast restriction site data, is supported by sequence data. The basal-most clade (ArcSyl) comprises Poa subgen. Arctopoa and subgen. Poa sect. Sylvestres, two groups having disparate morphology, but similar cpDNA. The next-diverging clade (BAPO), comprising sects. Bolbophorum, Alpinae, Parodiochloa, and Ochlopoa, is strongly supported and characterized by highly divergent cpDNA. The majority of Poa species and sections form a strongly supported clade comprising major clades SPOSTA, PoM, and HAMBADD. Newly reported in this study is Eremopoa as a distinct lineage positioned between this higher Poa clade and BAPO. A revised infrageneric classification of Poa comprising five subgenera is proposed. Two new subgeneric divisions of Poa are proposed: subgen. Stenopoa for the SPOSTA clade and supersect. Homalopoa for the HAMBADD clade. The monotypic genus Anthochloa is reduced to Poa sect. Anthochloa, and its one species recognized as Poa lepidula.

ABSTRACT. Poa, with about 575 species, is the largest genus of grasses, and has diversified throughout temperate, boreal, and arctic regions, and similar habitats through the tropics. This new phylogenetic study of Poa based on analysis of restriction site data from PCR amplified regions of chloroplast DNA expands previous sampling in the genus to where 1/5 to 1/6 of the species have been characterized for chloroplast DNA types. A broad phylogenetic structure detected in a previous study using restriction site mapping of Poa chloroplast DNA gained additional and robust support. Accounting for extended intra-and extrageneric sampling, Poa remains monophyletic if Austrofestuca and Parodiochloa are included as sections within P. Poa L. is the largest genus of grasses. Independent assessments by Clayton and Renvoize (1986) and RJS indicate there are about 500 or 575 species, respectively (Table 1). The genus has diversified throughout temperate, boreal, and arctic regions, and islands of similar habitats through the tropics, at all latitudes habitable by vascular plants. Poa exhibits both high species diversity and a high degree of endemism in many regions. For example, there are 34 endemic species in Malesia (Veldkamp 1994), 36 species in Australia (Sharp and Simon 2002), and 34 in New Zealand (Edgar 1986), with only two or three native species shared between Australia and New Zealand, and none shared between these areas and the rest of the world. Extensive polyploidy, hybridization, and few useful morphological characters combine to make Poa a taxonomically challenging genus.In contrast to other large grass genera (notably Festuca L. and Panicum L.), the monophyly of Poa has not been disproved, and no modern taxonomist nor data have seriously challenged its circumscription except by the removal of a few small, isolated groups of uncertain affinity. Modern revisions for several regions of the world have left Poa whole, or only removed one or a few species. In the opinion of RJS, there are few species that might be removed from the genus, but also a few small genera might be subsumed.

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.