New vascular plant records for the Canadian Arctic Archipelago

Abstract The Canadian Arctic Archipelago is a vast region of approximately 1,420,000 km2, with a flora characterized by low species diversity, low endemicity, and little influence by alien species. New records of vascular plant species are documented here based on recent fieldwork on Victoria and Baffin Islands; additional records based on recent literature sources are mentioned. This paper serves as an update to the 2007 publication Flora of the Canadian Arctic Archipelago, and brings the total number of vascular plants for the region to 375 species and infraspecific taxa, an increase of 7.7%. Three families (Amaranthaceae, Juncaginaceae, Pteridaceae) and seven genera (Cherleria L., Cryptogramma R. Br., Platanthera Rich., Sabulina Rchb., Suaeda Forssk. ex J.F. Gmel., Triglochin L., Utricularia L.) are added to the flora, and one genus is deleted (Minuartia L.). Five species are first records for Nunavut (Arenaria longipedunculata Hultén, Cryptogramma stelleri (S.G. Gmel.) Prantl, Puccinellia banksiensis Consaul, Saxifraga eschscholtzii Sternb., Utricularia ochroleuca R.W. Hartm.)


Introduction
Th e Canadian Arctic Archipelago (CAA) is a group of islands occupying the northern third of Canada extending about 3000 km south to north and east to west, and covering approximately 1.42 million square kilometers. Th e archipelago comprises three very large islands, Baffi n (507,451 km 2 ), Victoria (217,291 km 2 ), Ellesmere (196,236 km 2 ), twelve islands between 10,000 and 71,000 km 2 , and many thousands of smaller islands (Fig. 1). Politically the majority of islands are within the territory of Nunavut, while the westernmost part of the CAA is within the Northwest Territories. During the last glacial maximum (LGM) ice sheets covered almost the entire area; today glaciers cover only about 11% of the land area (Sharp et al. 2014). Th e Arctic fl ora as a whole is characterized as a young fl ora with low species diversity, low endemicity, and is little infl uenced by alien species (Daniȅls et al. 2013). Th ese characteristics are especially true for the fl ora of the CAA, which comprises only 349 recorded species and infraspecifi c taxa, no endemic species, and few, if any, stabilized alien species (Aiken et al. 2007).
Study of the Canadian Arctic Archipelago fl ora started with expeditions searching for a northwest passage in the early 1800s, such as the Parry Expedition (see Aiken et al. 2007 for a historical summary and list of collectors). Botanical collecting in this vast, diffi cult to access region continued sporadically through the 19 th and early 20 th centuries, mostly as part of large scientifi c expeditions. Th e fi rst regional vascular plant fl oras appeared in the mid-1900s: Polunin's (1940) Botany of the Eastern Canadian Arctic and Porsild's (1955) Vascular plants of the Western Canadian Arctic Archipelago. Soon after, Porsild (1957Porsild ( , 1964 published a fl ora covering the entire CAA. In 2007 Aiken et al. published an updated fl ora for the CAA in digital format using Delta software. Aiken et al. (2007) recorded and provided descriptions, maps and an interactive key for 349 species and infraspecifi c taxa (341 species plus eight subspecies) of vascular plants in the CAA, including three lycopods, eight monilophytes (ferns and Equisetum L.), and 338 fl owering plants (no gymnosperms present). Th e genus Papaver L. was not fully treated at the time because it was undergoing revision; Solstad (2007) provided a provisional key of fi ve species under the taxon entry Papaver spp., all of which are now recognized as distinct and occurring in the fl ora area (Elven et al. 2011). Counting these additional Papaver species (P. cornwallisense D. Löve, P. dahlianum Nordh., P. labradoricum (Fedded) Solstad & Elven, P. lapponicum subsp. occidentale (C.E. Lundstr.) Knaben, and P. sp. "Banks" [= P. hultenii Knaben]) brings the total to 353 species and infraspecifi c taxa (345 species), of which 342 are angiosperms. Aiken et al. (2007) comment in their Introduction that their fl ora "will provide a basis for much more research on Arctic plants in Canada in the coming years. Th ere are many potentially very interesting areas that have never been botanised…. In these sites, certainly new records, as well as interesting new species to the Arctic Archipelago, are waiting to be discovered." Recent fi eldwork by our team on Victoria Island in 2008 and 2010, and on Baffi n Island in 2012, led to discoveries of species new to the CAA and many signifi cant range extensions. Here we document our major fi ndings, including species, genera and families new to the CAA and species new to the western and eastern parts of the Arctic Islands. A subset of these are fi rst records of species for Nunavut. We also summarize the literature pertinent to the CAA fl ora published since 2007 (or that was not included in Aiken et al. 2007), including new species described, signifi cant new records, and new records resulting from taxonomic and nomenclatural changes. Th is publication serves as an update to Aiken et al. (2007).

Methods
Fieldwork in the CAA was carried out in 2008, 2010 and 2012. In July 2008 and 2010, we collected vascular plants on southern Victoria Island, Nunavut, and on north western Victoria Island, Northwest Territories ( Fig. 1) (map generated with SimpleMappr; Shorthouse 2010). In July 2012 we collected along the Soper River in Katannilik Territorial Park and in the vicinity of Kimmirut (formerly Lake Harbour) on southern Baffi n Island, Nunavut (Fig. 1). During these fi eld seasons we collected 3021 vascular plant numbers, of which 81 are reported here as new records, representing 25 taxa. Th e fi rst set of our collections is deposited in the National Herbarium of Canada (CAN), Canadian Museum of Nature. Duplicate specimens are deposited in ALA, ALTA, BABY, COCO, MICH, MO, MT, NYBG, O, UBC, US, UVIC, WIN, WTU (acronyms according to Th iers, continuously updated), as noted in the specimen citations. All specimens cited have been seen, unless otherwise noted. Species accounts are organized by major clade (monilophytes, monocots, and eudicots), and then alphabetically by family, genus and species. Family-level classifi cations follow Smith et al. (2006) for monilophytes and Angiosperm Phylogeny Group III (2009) for angiosperms. Numerous literature sources were consulted for nomenclature at the species level and below, including the Flora of the Canadian Arctic Archipelago (Aiken et al. 2007), the Flora of North America North of Mexico (Flora of North America Editorial Committee 1993+), and the Annotated Checklist of the Panarctic Flora (PAF): Vascular Plants (Elven et al. 2011). English common names mostly follow the Database of Vascular Plants of Canada (VASCAN) (Brouillet et al. 2010+, Desmet andBrouillet 2013). Global species distributions are modifi ed from Elven et al. (2011); they provided a summary of the main geographical distribution patterns but are not intended to be exhaustive. Images of CAN specimens cited under Specimens Examined are available on Figshare (http://fi gshare.com; see Appendix) and the Canadian Museum of Nature's collections online website (http://collections.nature.ca/en/Search).

Results
Th e new discoveries described here plus new species and signifi cant distribution records published recently bring the total number of vascular plant taxa in the CAA to 42 families, 141 genera and 375 species and infraspecifi c taxa (368 species). Table 1 provides a summary of these additions to the fl ora of the CAA since the publication of Aiken et al. (2007). Twenty species and infraspecifi c taxa are documented here as new to the CAA, representing a 7.7% increase in the number of species and infraspecifi c taxa recognized in Aiken et al. (2007).
Th ree families (Amaranthaceae, Juncaginaceae, Pteridaceae) and seven genera (Cherleria L., Cryptogramma R.Br., Platanthera Rich., Sabulina Rchb., Suaeda Forssk. ex J.F. Gmel., Triglochin L., Utricularia L.) are added to the fl ora. One genus (Minuartia L.) is deleted from the fl ora. We document six recently described taxa as additions to Aiken et al. (2007). Th ree new species have been described recently from the CAA: Draba simmonsii Elven & Al-Shehbaz (Elven and Al-Shehbaz 2008), widely distributed across the CAA, Draba cayouettei G.A. Mulligan & Al-Shehbaz from northern Quebec and Southampton Island (Al-Shehbaz and Mulligan 2013) and Puccinellia banksiensis Consaul from Banks Island and Arctic coastal Alaska (Consaul et al. 2008; its presence in Nunavut on Victoria Island is documented here). Harris (2006) Consaul et al. (2005) on Banks Island, although the precise identity of the single collection remains uncertain pending taxonomic revision of the species complex.
Several taxa are added to the fl ora of the CAA as a result of recent taxonomic revisions. Chrysosplenium rosendahlii Packer, described from Somerset Island (Packer 1963) but subsequently treated as a synonym of C. tetrandrum (Scoggan 1978, Aiken et al. 2007, is now considered a distinct species (Freeman and Levsen 2007), a status supported by molecular DNA barcode data (Saarela et al. 2013b). Papaver hultenii, described from the Coppermine River on mainland Nunavut and Alaska (Knaben 1959), was considered "apparently common on sandy and gravelly beaches and tundra ridges" on coastal mainland Northwest Territories and north-western mainland Nunavut by Porsild and Cody (1980: 335), but was subsequently treated as a synonym of P. lapponicum by Kiger and Murray (1997). Th e species has been confi rmed as distinct (Solstad 2009), and as occurring in the western CAA (Elven et al. 2011), where it is now known to be the dominant poppy species on southern Banks and Victoria Islands (collections at CAN and L.J. Gillespie, pers. obs.). Papaver sp. "Banks" of southern Banks Island (Solstad 2007(Solstad , 2009) is now considered conspecifi c with P. hultenii (H. Solstad, pers. comm.). Th e polyphyletic genus Minuartia has been divided into eleven genera (Dillenberger and Kadereit 2014), resulting in the addition of two genera, Cherleria and Sabulina, and the deletion of Minuartia from the fl ora of the CAA.
Several older publications and collections from the Arctic Islands have come to light since the publication of Aiken et al. (2007). While processing older collections at CAN, we became aware of a signifi cant range extension for Saxifraga eschscholtzii Sternb., previously known from only one locality in the CAA. Leymus innovatus subsp. velutinus (Bowden) Tzvelev, which was reported for Banks Island in Mason et al. (1972), Porsild and Cody (1980) and , was not included in Aiken et al. (2007). Its presence on Banks Island is confi rmed here. Additionally, the publication by Th annheiser et al. (2001) with many new distribution records for the Canadian Arctic Islands was overlooked by Aiken et al. (2007). Th is publication documenting the fl ora at specifi c sites on Victoria Island stemmed from fi eldwork focusing on plant ecology and phytosociology carried out between 1973 and 1998. No voucher collections were cited in the publication. Collections documenting some of the new records were located at TROM, but others, if they exist, could not be located.
Th annheiser et al. (2001) reported seven species as new to the CAA; of these, three are confi rmed here by our new collections (Andromeda polifolia L., Pinguicula vulgaris L., Suaeda calceoliformis (Hokk.) Moq.), two were not new records at the time (Poa hartzii Gand., reported earlier in Porsild 1957;Festuca hyperborea Holmen, reported in Porsild 1964), and two remain unconfi rmed (no voucher specimens found) but are likely not new records. One of these is Puccinellia deschampsiodes Th . Sör., a taxon now treated as a synonym of P. nuttalliana (Schult.) Hitchc. (Davis and Consaul 2007), which also includes P. borealis Swallen, previously known from Victoria Island (Porsild 1964, Porsild andCody 1980). Th e other is Parnassia palustris L., recorded from Johansen Bay; this material has likely been re-identifi ed as P. kotzebuei Cham. ex Spreng., which was recorded only from Hadley Bay but with Th annheiser collections present at TROM from both sites. Nine species were considered as new to the western CAA by Th annheiser et al. (2001). Of these, Sabulina stricta (Sw.) Rchb. is confi rmed here by our new collections and Carex microglochin Wahlenb. was confi rmed and included in Aiken et al. (2007). Two were not new records: Puccinellia langeana subsp. typica T.J. Sørensen ex Hultén [= P. tenella subsp. langeana (Berlin) Tzvelev] was reported in Porsild (1964), and Hedysarum alpinum L., for which two subspecies were recorded, but only one, H. alpinum subsp. americanum (Michx. ex Pursh) B. Fedtsch. [= H. americanum (Michx. ex Pursh) Britton], is considered present in the Arctic (Porsild 1957, Porsild and Cody 1980, Elven et al. 2011. Koenigia islandica L. and Eleocharis acicularis (L.) Roem. & Schult. could not be confi rmed since no voucher specimens Table 1. Vascular plant species new to the Canadian Arctic Archipelago (CAA) since the publication of Aiken et al. (2007). Records are based on fi eld collections and literature sources. Species new to the CAA, western CAA, eastern CAA and Nunavut are given. New records for one adventive species, one species previously known from only one collection in the CAA, one recently described species, and confi rmation of three species excluded by Aiken et al. (2007) are also included.  Mason et al. (1972), Porsild and Cody (1980),  were located, Potentilla nivea L. subsp. nivea could not be confi rmed since it belongs to a taxonomically diffi cult species complex that has changed over time and largely remains poorly resolved, and two species remain to be confi rmed, which also belong to taxonomically diffi cult species complexes (Cerastium alpinum L., Castilleja caudata (Pennel) Rebrist.; a specimen of the latter at TROM was determined as Castilleja cf. caudata by R. Elven and I. Alsos). Th e majority of the new records described here are assumed to be discoveries of long established species that have simply been overlooked by botanists. One record, Hordeum jubatum L., an introduced weedy species found within the Kimmirut town site, is obviously a recent introduction. Documenting the present day fl ora is essential as baseline data for future studies of fl oristic changes resulting from the warming climate or from anthropogenic introductions due to increased human traffi c.

MONILOPHYTES Pteridaceae
Cryptogramma stelleri (S.G. Gmel.) Prantl Fig. 2 Common name. Steller's rockbrake Distribution. Disjunct circumboreal (absent from Greenland and Europe) Comments. Th is is the fi rst record of the species, genus and family from the CAA and for Nunavut. Th e genus is easily distinguished from other fern genera in the Arctic Islands by its dimorphic fronds. We discovered one small population on a southeast facing cliff by Fundo Lake on the outskirts of Kimmirut. Plants were small with sterile fronds 3-5(7) cm long and fertile fronds 4-8 cm long, and were growing with moss in horizontal fractures in grey marble.
Uncommon and with a scattered and disjunct distribution, C. stelleri is found in North America primarily in the western montane boreal and eastern boreal zones (Alverson 1993). It is listed in North America as apparently secure only in Ontario and Quebec, vulnerable to critically imperilled in all other provinces, and vulnerable to possibly extirpated in all states where it occurs and is ranked (NatureServe 2014). Typical habitat in North America is considered to be crevices and rock ledges on calcareous cliff s in boreal habitats (Alverson 1993). Absent from most of the Northwest Territories, Porsild and Cody (1980) recorded it as rare on moist shale slopes in the Richardson and Mackenzie mountains. In northern Quebec it occurs in several small isolated populations mostly in coastal areas near treeline, in cracks on moist shady calcareous cliff s or sometimes on granitic rock in moist, low acid soils on ledges and overhangs (Dignard 2013). Th ree nearby sites on rocky escarpments near Kangiqsujuaq on the northern Quebec coast occur well within the Arctic (ca. 61°36'N). Our collection from 62°50'44"N on nearby Baffi n Island represents a new northern limit for eastern North America. Low spore production, limited dispersal ability, and restricted habitat preference are thought to contribute to its rarity and scattered distribution (Peck et al. 1990, Dignard 2013, and also suggests that this diminutive fern may simply have been overlooked in the past, rather than representing a recent introduction. Specimens examined. Canada. Nunavut: Qikiqtaaluk Region, Baffi n Island, Kimmirut, W end of Fundo Lake, ca. 2 km W of hamlet, 62°50'44"N, 69°54'6"W, 40 m, 22 July 2012, Saarela, Gillespie, Sokoloff & Bull 2774 (ALA, CAN-601315).

Common name. Two-coloured sedge
Distribution. Circumpolar-alpine Comments. Th is is the fi rst report of the species from the western CAA, based on one collection from a sloped sandy riverbank on southern Victoria Island, Nunavut. Th e species is known from the southeastern CAA (Coats Island, Southampton Island, southern Baffi n Island; Cody 1980, Aiken et al. 2007). In the western Arctic, Carex bicolor is known from adjacent mainland Nunavut (Bathurst Inlet) and Northwest Territories Cody 1980, Saarela et al. 2013a).

Common name. Brownish sedge
Distribution. Circumboreal-polar Comments. Th is is the fi rst report of the species from the CAA. Our collections were gathered in Katannilik Territorial Park on southern Baffi n Island, where the cespitose species was found at three sites in damp, turfy places. It was rare at two sites (only a few scattered plants), and locally common at one site. Associated species include Betula glandulosa Michx., Calamagrostis canadensis var. langsdorffi i (Link) Inman, Chamerion angustifolium (L.) Holub, Carex arctogena Harry Sm., C. bigelowii Torr. ex Schwein., Pedicularis lapponica L., Poa arctica R. Br. and Taraxacum ceratophorum (Ledeb.) DC.

Common name. Wahlenberg's woodrush
Distribution. Circumpolar-alpine Comments. Th is is the fi rst collection of this low Arctic species from the western CAA. Th e taxon is known from several sites on adjacent mainland Nunavut (Porsild and Cody 1980, Cody et al. 1989, Cody 1996, Cody and Reading 2005. Our collection represents a range extension in the central portion of its range of some 330 km northnorthwest of the nearest site on mainland Nunavut (George Lake Camp, 65°55'10"N, 107°23'00"W, Reading 466, DAO; Cody and Reading 2005). Th is taxon is now known from eight sites in the CAA: the one reported here, and seven on southeastern Baffi n Island. Elsewhere in the Canadian Arctic there are numerous collections of the species from northern Quebec and northwestern North America (Alaska, Yukon, western mainland Northwest Territories) (Porsild and Cody 1980, Swab 2000, Kirschner 2002, Hay 2013. Specimen examined. Canada. Nunavut: Kitikmeot Region, Victoria Island, fl at topped steep sided hill, 11 km NE of Johansen Bay airstrip, 68°39'12"N, 110°54'47"W, 120 m, 20 July 2008, Gillespie, Saarela, Consaul & Bull 8170 (CAN-592326).
Juncaginaceae Triglochin palustris L. Fig. 4 Common name. Marsh arrowgrass Distribution. Circumboreal-polar Comments. Discovery of this widely-distributed temperate and facultatively halophytic species growing in wet, brackish habitats at two sites on southern Baffi n Island adds a new monocot family, Juncaginaceae, to the fl ora of the CAA. Th is taxon is diminutive on Baffi n Island, ranging from 6-12 cm tall (larger elsewhere in its range, up to 42.5 cm tall; Haynes and Hellquist 2000a) and therefore easily overlooked, particularly when in fl ower (fruiting plants are more noticeable). On the mainland, it is known from several Arctic coastal and near-coastal sites in adjacent northern Quebec Cayouette 2002, Hay 2013) and from a few sites on mainland Nunavut and the Northwest Territories (Porsild and Cody 1980, Blondeau and Cayouette 2002, Saarela et al. 2013a) and southern Greenland (Haynes and Hellquist 2000a). Th e larger and more robust species Triglochin maritima L., which occurs on the mainland Arctic (Porsild and Cody 1980, Hay 2013, Saarela et al. 2013a, is not known from the CAA. One collection was gathered from a population in wet sandy ground in a dried up depression adjacent to meromictic Soper Lake, associated with Eriophorum scheuchzeri Hoppe, Juncus arcticus Willd., Carex bicolor, and Dupontia fi sheri R. Br. Th e second collection was gathered from a sedge meadow at the input of Fundo Lake, associated with Carex atrofusca Schkuhr, C. gynocrates Wormsk. ex Drejer, C. membranacea Hook., C. microglochin, C. rarifl ora (Wahlenb.) Sm., C. scirpoidea, Eriophorum angustifolium, E. callitrix Cham., E. russeolum Fr., E. scheuchzeri, Juncus arcticus, Kobresia simpliciuscula (Wahlenb.) Mack. and Trichophorum caespitosum (L.) Hartm.  Fig. 5 Common names. Northern coralroot, early coralroot Distribution. Circumboreal-polar Comments. Our collections represent the fi rst record of the species in the western CAA, and the second for the eastern CAA and Baffi n Island. Th ought to be the only orchid in the CAA (Aiken et al. 2007, but see Platanthera obtusata), it was previously known from only one collection and two sites in Auyuittuq National Park, Baffi n Island (Gould 1997). Common throughout boreal Canada, its range is scattered and sparse north of the tree-line to the mainland Arctic coast from the Yukon to Bathurst Inlet, Nunavut, and along the Hudson Bay coast (Porsild and Cody 1980). In their treatment of Corallorhiza trifi da for the Flora of North America, Magrath and Freudenstein (2002) reported the species from the western CAA. Th ey mapped two dots on Victoria Island: one centered on the Cambridge Bay area, the other on south-central Victoria Island; and they shaded the southern half of Prince of Wales Island. We are not aware of specimens or other literature reports for these records; they do not appear in Freudenstein's (1997) revision of Corallorhiza in North America, nor does J. Freudenstein (pers. comm. 2014) know the source of these records (L. Magrath, fi rst author of the FNA treatment, is deceased). Our collection from south-central Victoria Island (incidentally, this is one of the same areas mapped in Magrath and Freudenstein 2002) is the only confi rmed record for the western CAA. It was recorded as uncommon on the low, densely vegetated, south-facing bank of a creek near its mouth, on a mostly sandy substrate, with Dryas integrifolia, Bistorta vivipara (L.) Gray, and Hedysarum boreale subsp. mackenziei (Richardson) S.L. Welsh (Salix and Arctous rubra (Rehder & E.H. Wilson) Nakai nearby).

Corallorhiza trifi da Chatelain
In the Soper River valley on southern Baffi n Island we found the species to be scattered, but never common, on densely vegetated river fl ats, riverbanks, and peaty wet meadows at several localities. Our three collections increase the number of records for Baffi n Island to four. In adjacent northern Quebec, the species occurs along the coast and in the interior, known from only three Arctic localities (Houle 2013).
Th e species is a near-complete mycoheterotroph (Zimmer et al. 2008, Cameron et al. 2009), and in most of its range plants are green to yellow-green in colour (e.g., see photo in Houle 2013: 322). Freudenstein (1997) noted that lighter-coloured individuals tend to occur in more southern, forested areas, whereas darker-coloured forms occur in exposed northern sites, such as tundra. Earlier observations of the species at its northern limits in Canada are consistent with this (Gould 1997, Saarela et al. 2013a). Our collection from Victoria Island was prominently reddish-brown throughout (anthocyanic) ( Fig. 5A-C); those from the Soper River valley less so (Fig. 5D). None of the populations we observed was as large as a population of 56 individuals found in Auyuittuq National Park of Canada, Baffi n Island (Gould 1997). One population collected and surveyed in the Soper River valley had 19 stems in a 5 × 3 m area (Saarela et al. 1970); the population collected on Victoria Island had 14 stems in two clumps (Gillespie et al. 8093). A fourth occurrence was observed but not collected in the Soper River valley (near confl uence of Willow River, ca. 14 km S of Mount Joy, 63°9'24"N, 69°41'35"W). Habenaria obtusata (Banks ex Pursh) Richards Lysiella obtusata (Banks ex Pursh) Rydb.

Common name. Northern bog orchid
Distribution. Boreal North America Comments. Th is is the fi rst record for this genus and species, and the second species of orchid discovered (see Corallorhiza trifi da), in the CAA (Aiken et al. 2007). Th e species is currently considered to include two subspecies; all North American plants belong to subsp. obtusata, while Eurasian plants are treated as subsp. oligantha (Turcz.) Hultén (Sheviak 2003, Elven et al. 2011. Th is wide-ranging boreal species of damp or wet, turfy places (Correll 1978) is also found beyond the treeline in Canada from northern Yukon to northern Quebec (Porsild and Cody 1980, Cody 2000, Cody et al. 2003, Sheviak 2003, Saarela et al. 2013a). Porsild (1955) suggested that the species is likely to be found in southern areas of the western Arctic Islands, but it has not yet been found there. In Arctic Quebec, the species has been reported as occurring along the east coast of Hudson Bay (Polunin 1940, Porsild and Cody 1980, Sheviak 2003, Houle 2013) and at fi ve sites on the north-central Ungava Peninsula (Maycock and Matthews 1966, Blondeau and Cayouette 2002, Houle 2013. Blondeau and Cayouette (2002) reported the species from two sites near Douglas Harbour along the northern coast, just south of Kimmirut, Baffi n Island (mapped in Houle 2013). At one site the species was uncommon at the base of a scree slope along a stream margin, and at the second only a few individuals were found growing among rocks. Along the Soper River on southern Baffi n Island we collected three populations. Th e fi rst (Saarela et al. 2197) had two subpopulations with a total of 80 plants, the second (Saarela et al. 2209) came from a population of over 100 plants in a 10 m 2 area, and the third (Saarela et al. 2488) was from a population of over 250 plants in a 80 m 2 area. Near the third population was an even larger population estimated at over 1000 plants that was not collected. Th ese populations were found in moist sedge-willow hummocks set on small hills and valleys on the lower slopes of the Soper Valley away from the banks of the Soper River, growing in association with Betula glandulosa, Salix arctophila Cockerell ex A. Heller, S. calcicola Fernald & Wiegand, S. reticulata, Empetrum nigrum L., Rhododendron lapponicum (L.) Wahlenb., Equisetum arvense L., Cassiope tetragona (L.) D. Don, Vaccinium uliginosum L., and V. vitis-idaea L. While the fi rst two populations were encountered within a few kilometers of each other, we encountered the third, largest population 20 kilometers away, suggesting that other populations may occur in the area where habitat is suitable. Common name. Slim-stemmed reedgrass Distribution. Circumboreal-polar Comments. Our new collections confi rm the presence of this taxon in the eastern CAA. We collected specimens from several populations in Katannilik Territorial Park on southern Baffi n Island, in mesic to wet tundra habitats. Th e species is documented in the western CAA (Banks Island, Melville Island, Prince Patrick Island; Aiken et al. 2007, as C. neglecta subsp. groenlandica (Schrank) Matuszk). Porsild and Cody (1980) reported the taxon (as C. neglecta (Ehrh.) G. Gaertn., B. Mey. & Scherb.) from Devon Island, the Cumberland Peninsula of Baffi n Island and Coats Island, but these records were not mapped in Aiken et al. (2007), nor could specimens be located at CAN or DAO. Associated species on Baffi n Island include Agrostis mertensii Trin., Arctagrostis Hordeum jubatum L. subsp. jubatum Fig. 8 Common name. Foxtail barley Distribution. North America-NE Asia Comments. Hordeum jubatum is a widely distributed species that grows in meadows, along rivers, around lakes, and in disturbed habitats such as roadsides (von Bothmer et al. 2007). Two subspecies are recognized: subspecies jubatum and intermedium Bowden, which diff er in the lengths of their glumes and lemma awns of the central spikelets (Bowden 1962, von Bothmer et al. 2007; the variation in these characters is continuous and some intermediate specimens cannot be assigned to subspecies (Bowden 1962, Baden andvon Bothmer 1994). Bowden (1962) considered subsp. intermedium to be a hybrid between H. jubatum s.s. and H. brachyantherum Nevski, but to our knowledge this hypothesis has not been tested with molecular data. Some authors treat subsp. intermedium as a separate species, H. caespitosum Scribn. (e.g., Baum and Bailey 1994). Hordeum jubatum subsp. jubatum is a weedy species native from eastern Siberia and northeastern China through North America to Mexico, and it is introduced to South America, Europe and Central Asia von Bothmer 1994, von Bothmer et al. 2007). It is generally considered to be native in western North America and adventive in eastern and southeastern North America (e.g., Hitchcock 1951, von Bothmer et al. 2007), but some authors consider it native across North America (Baden and von Bothmer 1994). Bowden (1962) noted the subspecies to be expanding its range in northern Canada. Hordeum jubatum subsp. intermedium grows in central and western Canada and United States, the Magdalene Islands, Quebec, and is disjunct in southern Mexico (Bowden 1962, Baden and von Bothmer 1994, von Bothmer et al. 2007. Although the species is distributed primarily in temperate and sub-Arctic regions of North America there are sporadic collections of both subspecies from Arctic regions of Alaska (Klein 2011, Skinner et al. 2012) and Canada. On Canada's mainland Arctic, H. jubatum subsp. intermedium has been recorded from Hood River, Nunavut (Anderson 473 in 1915, CAN-39857 & CAN-514373;Macoun andHolm 1921, Bowden 1962) and from Tuktoyaktuk, Northwest Territories (Aiken & McLachlan 87-221 in 1987, CAN-530893). Two records of H. jubatum s.l. from Ungava Bay in northern (Arctic) Quebec and one from western Greenland are mapped in von Bothmer et al. (2007).
Hordeum jubatum was apparently accidentally introduced as early as the 1960s to Apex (near Iqaluit, Baffi n Island, CAA) with straw used as animal feed and/or packing material (Aiken et al. 2007). Plants were observed (and collected) in the same area (around the Hudson's Bay Company house) in the mid-to late-1980s (Aiken, Campbell & Robinson 86-445 in 1986, CAN-518325;Aiken, Campbell & Robinson 86-337 in 1986, CAN-518217;Aiken 89-115 in 1989, CAN-541784). Th ese three specimens were not previously determined to subspecies. Th e two 1986 collections are intermediate between subspecies jubatum and intermedium and the 1989 collection is subsp. jubatum. It is unknown if these collections represent the same or separate introductions. Th e species was observed in the same area in 1998 and 2002 (no collections were made), but the site was overgrown by willows in 2005 and the species was absent (Aiken et al. 2007). We were at the site in July 2012 and did not encounter the species. Th ere is also a 2003 collection from a separate locality in nearby Iqaluit (across from Joamie Ilinniarvik School, Mallory s.n., . Th e label on this specimen indicates "possibly an accidental introduction as part of earlier project to hydro-seed grass around the school." It is not known if the species persists in the Iqaluit area. We found three robust plants of H. jubatum subsp. jubatum in the community of Kimmirut in 2012, adding a second area of occurrence for the species on Baffi n Island. Two plants were growing in a lush sewage runoff area near the garbage dump on slopes well above the coastal high tide line with Chamerion latifolium (L.) Holub, Poa alpina L., P. glauca Vahl, Salix glauca L., Stellaria longipes Goldie and Taraxacum lapponicum Kihlm. ex Hand.-Mazz., and one in the hamlet, growing on a rocky, sandy beach adjacent to the coast associated with Poa arctica and Taraxacum lapponicum (Fig. 8). Based on the few individuals found in Kimmirut, these likely represent very recent introductions, which may have arrived naturally (dispersal by birds, for example) or been introduced unintentionally by humans. Th e presence of this species in Kimmirut should be monitored to determine if it is increasing its presence there, particularly at the sewage runoff site where a high nutrient load supports lush plant growth (J.M. Saarela and P.C. Sokoloff , pers. obs.).

Leymus innovatus subsp. velutinus (Bowden) Tzvelev
Common Name. Northern downy ryegrass Distribution. American Beringia Comments. Although not reported in Aiken et al. (2007) for the CAA, this species was fi rst reported for the CAA from Banks Island by Mason et al. (1972, as Barkworth, 1993), that has been re-determined as this species (det. J.M. Saarela). Th e taxon was mapped on southern Banks Island by Porsild and Cody (1980) and , probably based on the Mason collection and/or one or more correctly-determined duplicates of the Sachs Harbour collection in other herbaria. It grows in Alaska, the Yukon Territory, and the western Northwest Territories    (Bowden 1957, Elven et al. 2011. Leymus mollis subsp. villosissimus is an Arctic taxon, distributed from Siberia to Greenland, and common in the low CAA, while subsp. mollis grows along the east and west coasts of North America, along the Arctic coast of Quebec, in some interior locations (Great Slave Lake, for example) and in Greenland (Bowden 1957, Aiken et al. 2007. Subspecies mollis has not previously been reported from the CAA (Bowden 1957, Aiken et al. 2007) and our collection from southern Baffi n Island is thus the fi rst record for the region. Th e collection was made on the outer sandy fl oodplains of Soper Lake, where the species was uncommon; subspecies villosissimus was more common in the region.  Fig. 9 Common name. Dwarf alkaligrass Distribution. Arctic NW North America Comments. Th is species was described recently from three localities on southern Banks Island, Northwest Territories, and one locality in northern Alaska (Consaul et al. 2008). Saarela et al. (2013a) reported two collections from the lower Brock River on mainland Northwest Territories. Here we report six new localities for the species from southwestern Victoria Island-the fi rst records for this island and for Nunavut, expanding the species' range eastwards in the CAA.  Following the treatment by Kaplan (2008) S. vaginata may be distinguished by its open leaf sheaths from S. fi liformis (Pers.) Börner, the only species of the family known to occur in the CAA prior to this collection. Although S. vaginata is generally more robust in habit with wider leaf sheaths and more numerous whorls of fl owers on the infl orescence (usually 7-9 versus 3-6 in S. fi liformis), our collection from the northern edge of its range was somewhat intermediate in size with few young infl orescences (and no fruit) having 5-7 whorls of fl owers.

Puccinellia banksiensis Consaul
Th e taxonomy of Stuckenia Borner is complex and there are several confl icting taxonomic treatments (e.g., Tolmachev et al. 1995, Haynes and Hellquist 2000b, Kaplan 2008; see discussion in Elven et al. 2011). Our collection was initially identifi ed by R. Elven in 2009 as S. subretusa (Hagstr.) Holub, a primarily Russian Arctic species, based on its retuse or subretuse leaf apices. Although included in the Panarctic Flora, Elven et al. (2011) were not fully convinced that it should be treated as distinct and suggested a possible alternative treatment within a variable S. fi liformis. Tolmachev et al. (1995) recognized S. subretusa in their treatment for the Russian Arctic, but suggested it might be an arctic race of S. vaginata. Kaplan (2008) in his revision of Asian Stuckenia treated S. subretusa as a synonym of S. vaginata (both have open leaf sheaths contrasting with the fused leaf sheaths of S. fi liformis); he found leaf apex shape to vary within specimens and (sub)retuse leaf apices on collections from across the range of S. vaginata. Saarela et al. (2013b) in their barcode study of Canadian Arctic Island vascular plant species found that the rbcL and matK sequences of our collection (as S. subretusa) were identical to those of S. vaginata, and diff erent from S. fi liformis, consistent with Kaplan's (2008) treatment. Here we follow Kaplan (2008) in treating S. subretusa as a synonym of S. vaginata, but also recognize that the species complex in North America is in need of further study. If S. subretusa is considered a distinct species, our collection would represent the fi rst record for Canada (and is the one referred to in Elven et al.

EUDICOTS Amaranthaceae
Suaeda calceoliformis (Hook.) Moq. Fig. 11 Common name. Horned sea-blite Distribution. North America Comments. Th is species was fi rst recorded as occurring at Johansen Bay along southern Victoria Island by Th annheiser et al. (2001; voucher at TROM, not seen); however, the species was not included in Aiken et al. (2007) and we thus report it here. We collected S. calceoliformis at fi ve sites on Victoria Island: three on southern Victoria Island (Nunavut), and two in the vicinity of Minto Inlet on north-western Victoria Island (Northwest Territories). Th ese are the fi rst records for this family, genus and species in the CAA. We initially mis-identifi ed our collections as the annual Koenigia islandica (Polygonaceae), a superfi cially similar species known from the adjacent mainland and the eastern Arctic Islands (Aiken et al. 2007, Porsild andCody 1980). Th e true identity of our material was revealed upon collection of DNA barcode data (Saarela et al. 2013b), which placed them with other Suaeda individuals and distinct from Koenigia. Re-examination of the very small specimens confi rmed their identity as S. calceoliformis.
Th is species is found in saline and disturbed environments in the western and midwestern United States north to south-western Yukon, along southern James Bay and coastal areas of eastern Canada and north-eastern United States (Bassett and Compton 1978, Cody 2000, Riley 2003, Ferren Jr. and Schenk 2004. It is also known from one sub-Arctic site on the northern side of Great Bear Lake and four areas in the western mainland Arctic: Tuktoyaktuk Peninsula; Rae River mouth, Kugluktuk area; Walker Bay, Kent Peninsula; and Paulatuk and Lower Brock Lagoon (Bassett and Compton 1978, Cody et al. 2003, Ferren Jr. and Schenk 2004, Porsild and Cody 1980; specimen citations given in Saarela et al. 2013a). Th e species was treated as a rare plant for the Canadian Arctic (McJannet et al. 1993). Our fi ve collections from Victoria Island double the number of known sites for this species in the Canadian Arctic. It has probably been overlooked by collectors in its Arctic range, as it is very small and has fairly specialized habitat requirements.
Suaeda calceoliformis displays a wide degree of phenotypic plasticity throughout its range; for example, its height ranges from 5 cm to 1 m in continental Canada (Ferren Jr. and Schenk 2004). Our collections range from 1-4 cm, with the smallest plants often only possessing a single infl orescence. Habitats on Victoria Island include saline depressions inland and coastal saline fl ats, and the species was typically found growing in association with Puccinellia arctica (Hook.) Fernald & Weath. and P. phryganodes (Trin.) Scribn. & Merr.
Caryophyllaceae Arenaria humifusa Wahl. Fig. 12 Common name. Creeping sandwort Distribution. Arctic North America-amphi-Atlantic Comments. Our collections from the Minto Inlet area of Victoria Island represent the fi rst record of the species from the western CAA. Plants were matted, often large, forming loose circular cushions and were found growing on inland sand dunes. Although the species is primarily distributed in the eastern Canadian Arctic and sub-Arctic (south to Nova Scotia) and around Hudson Bay, it is also found scattered on the Northwest Territories and Nunavut mainland south of Victoria Island (specimens at CAN). Porsild and Cody (1980) treated A. humifusa in the broad sense including A. longipedunculata (see below) and the distribution shown for Alaska, Yukon, and part of the Northwest Territories is that of the latter species. Neither species has previously been recorded for the western Arctic Islands Cody 1980, Aiken et al. 2007). Our Minto Inlet collections have short pedicels (0.5-4 mm long) with mostly very short retrorse hairs (and few scattered glandular hairs), fl owers not exserted above the leaves, glabrous sepals and smooth leaf margins, all characteristics of A. humifusa s.s. Specimen examined. Canada. Northwest Territories: Inuvik Region, Victoria Island, Sand dunes east of Kuujjua River, 2 km south of lower Kuujjua River, 71°10'4.8"N, 116°27'54"W, 110 m, 16 July 2010, Gillespie, Saarela, Doubt, Bull & Sokoloff 9882 (ALA, CAN-599149, O); Inuvik Region, Victoria Island, Sand dunes east of Kuujjua River, 2 km south of lower Kuujjua River, 71°10'4.8"N, 116°27'54"W, 110 m, 16 July 2010, Gillespie, Saarela, Doubt, Bull & Sokoloff 9893 (ALA, CAN-599166, O); Inuvik Region, Victoria Island, sandy bank of Kuujjua River, south of "Fish Lake", 71°6'43.2"N, 116°6'21.2"W, 74 m, 17 July 2010, Gillespie, Saarela, Doubt, Bull & Sokoloff 9971 (CAN-599167).

Arenaria longipedunculata Hultén
Common name. Long-stemmed sandwort Distribution. Arctic-alpine amphi-Beringia-North America Comments. Our collections are the fi rst records of the species for the CAA and Nunavut. Described by Hultén (1966) from Arctic Alaska, this species was considered conspecifi c with Arenaria humifusa by Porsild and Cody (1980), but has most recently been treated as a separate species (Cody 2000, Elven et al. 2011. While considered to have an amphi-Beringian distribution, Elven et al. (2011) suggested that the species may also be present in the CAA and Greenland based on the results of a phylogeographical analysis of AFLP data (Westergaard et al. 2011), a hypothesis supported here. Our collections from southeastern Victoria Island (det. R. Elven) and Baffi n Island were identifi ed as this species based on the character combination of long pedicels (10-20 mm) with glandular villous pubescence (not very short retrorse), fl owers long-exserted above the leaves, sepals glandular villous basally, and leaf blade margins ciliate proximally (at least sparsely) . We found that pedicel length varied among collections and was sometimes shorter than the range given for A. longipedunculata (10-20 mm) in Hartman et al. (2005); however, other characters were consistent with our identifi cation. Pedicels are 10-20 mm (Saarela et  al. 2776) and 5-10 mm long (Saarela et al. 2477) on the Baffi n Island collections, and 9-12 mm long (Gillespie et al. 7721) on the Victoria Island collection (fl owers were still in bud with pedicels up to 6 mm long on Gillespie et al. 8136). Plants were small and tufted, and were growing in moss on moist to wet riparian meadows on Victoria Island and in mossy tundra at base of slopes or cliff s on Baffi n Island.
Th e ranges of A. longipedunculata and A. humifusa overlap in the Arctic Islands; indeed we collected both species in the Soper River-Kimmirut area on Baffi n Island, and both on Victoria Island but in diff erent localities. In northern Quebec and Newfoundland some large specimens identifi ed as A. humifusa appear to approach A. longipedunculata in some characters; these robust matted plants have elongate stems with long internodes and pedicels. Further study of this species complex is needed to determine more precisely species boundaries and distributions and to determine if hybrid or introgressed populations exist in the Canadian Arctic.

Common name. Bog stitchwort
Distribution. Circumpolar-alpine Comments. Th is species was fi rst recorded for the western CAA, on southern Victoria Island, by Th annheiser et al. (2001;no voucher collection located), and is confi rmed by our collection. Th e species is known from Baffi n, Southampton, and Coats Islands in the eastern Arctic Islands, and has a scattered distribution across the low Arctic (and north-west alpine areas) from Alaska to Labrador and Greenland. On mainland Nunavut it is currently known only from the Hudson Bay area, and in the Northwest Territories from the vicinity of Great Bear Lake and the Hornaday River Cody 1980, Saarela et al. 2013a). Th e Victoria Island collections represent a range extension of ca. 400 km northeast of the Northwest Territories populations and ca. 1000 km west of the closest Nunavut population.
Sabulina stricta may be distinguished from the closely related and largely sympatric Sabulina rossii-S. elegans species complex by the presence of branched fl owering stems bearing two or more fl owers (versus always unbranched and 1-fl owered in the latter). Recent molecular evidence suggests that S. stricta may be part of this species complex and not easily separable from the genetically diverse species S. elegans (Saarela et al. 2013b, S. Leung and L.J. Gillespie, unpubl. data).

Ericaceae
Andromeda polifolia L. Fig. 13 Common name. Bog rosemary Distribution. Circumboreal-polar Comments. Th is species was fi rst reported from the Arctic Islands by Th annheiser et al. (2001; no voucher collection located for confi rmation), at Johansen Bay on the southern coast of Victoria Island; however, it was not included in Aiken et al. (2007). We collected it at Johansen Bay, confi rming its presence there, and along the Soper River on southern Baffi n Island, extending the range of this boreal species northwards across the low Arctic islands.
Andromeda polifolia has a broad circumboreal-polar distribution, and occurs from Alaska across much of Canada and northern United States to western Greenland (Fabijan 2009). Numerous collections have been reported from the mainland Arctic Cody 1980, Saarela et al. 2013a), including sites south of Coronation Gulf across from our collection site on Victoria Island. On Victoria Island we encountered a single, large population of the species growing in dense moss-sedge mats along the sides of hummocks and polygon ridges in a hummocky, moist to wet sedge meadow on a gentle west-facing slope, in association with Dryas integrifolia, Arctous rubra, Vaccinium uliginosum, Rhododendron tomentosum subsp. decumbens, Salix reticulata, Cassiope tetragona and Carex spp. We collected the species in the Soper River valley, Baffi n Island, in a large, wet and hummocky sedge meadow, growing in association with Carex rarifl ora, Betula glandulosa, Salix arctophila, and Luzula wahlenbergii. We observed three patches at this location, one 3 × 2 m, and two smaller ones along the edge of a pond. Our collection in this area was made on the east side of the Soper River; we also observed the species in the area on the west side of the river, but did not collect it there. Elven et al. (2011) provisionally treat Andromeda polifolia as two subspecies-the Eurasian A. polifolia subsp. polifolia and the widespread A. polifolia subsp. pumila V.M. Vinogr. However, due to diffi culties in circumscribing diagnostic characters this division is diffi cult to quantify, and they call for an in depth investigation of this taxon. Fabijan (2009)
Common names. One-sided wintergreen, nodding wintergreen Distribution. Disjunct circumpolar (excluding Europe) Comments. Th is is the fi rst collection of the species from the eastern CAA; previously it had been collected in the western Arctic Islands at two localities on Victoria Island (Aiken et al. 2007), where we also collected it from a third locality, and one on Banks Island (Porsild and Cody 1980; not mapped in Aiken et al. 2007). In the eastern North American Arctic, this species is known from western Greenland (Böcher et al. 1968) and Ungava Bay, Quebec (Porsild and Cody 1980), thus our collection fi lls in a distributional gap in the general area between these sites, extending the range to southern Baffi n Island. Our collection on Baffi n Island comes from a single population encountered along the Soper River. Th is small population was found growing abundantly in a wet snowbed community with Cassiope tetragona, Vaccinium uliginosum, and Salix reticulata. On Victoria Island, we found this species growing in a similar habitat: a wet sedge meadow formed by a drainage between two lakes, associated with Carex aquatilis var. minor, Eriophorum angustifolium, Dryas integrifolia, Salix reticulata, S. glauca, and Pedicularis albolabiata (Hultén) Kozhevn.  Elven et al. (2011) recognize this taxon at the species level as Orthilia obtusata (Turcz.) H. Hara, a circumpolar plant distinct from the mostly circumboreal O. secunda (L.) House. Freeman (2009) treats North American material as widely variable, and synonymises subsp. obtusata under Orthilia secunda. As there are distinctions between the taxa, most pronounced in Eurasia, we follow Aiken et al. (2007), and treat the Arctic taxon as O. secunda subsp. obtusata, an approach intermediate to those of Elven et al. (2011) andFreeman (2009).

Fabaceae
Oxytropis defl exa subsp. foliolosa (Hook.) Cody Fig. 14 Common name. Pendant-pod oxytrope, pendant-pod locoweed Distribution. Arctic-alpine North America Comments. Th is is the fi rst record of this taxon from the western CAA-the only populations known on the islands previously occur on southeastern Baffi n Island near Kimmirut, Iqaluit, and on the Hall Peninsula (Aiken et al. 2007), and we made four additional collections in Katannilik Territorial Park on southern Baffi n Island. On the mainland Arctic, this taxon has been collected in the vicinity of Coronation Gulf south of Victoria Island (67°45'N, 111°57'W) (Macoun and Holm 1921). Subspecies foliolosa is common in the boreal forest of Yukon and Alaska, extends south along the Rocky Mountains to Colorado, and occurs along the coast in northern Ontario and Quebec (Welsh 1974, Porsild and Cody 1980, Blondeau and Cayouette 2002. A collection (Baldwin 1997, CAN-203476) from the vicinity of Longstaff Bluff (68°58'N, 47°57'W) on the west coast of Baffi n Island is included in the range map for this species in Porsild (1957). However, Porsild re-identifi ed this collection to Astragalus alpinus L. in 1959 (a determination with which we agree) and, while the dot on the map is erroneously reproduced in Porsild and Cody (1980), it is correctly omitted from the map in Aiken et al. (2007). We encountered only one small population on Victoria Island, consisting of six individuals growing on a rocky river fl at at the edge of a low thicket of Salix alaxensis (Andersson) Coville, associated with Chamerion latifolium, Astragalus alpinus, Castilleja elegans Malte and Saxifraga tricuspidata Rottb. Th is collection extends the range of this species north by approximately 300 kilometers from Coronation Gulf, where J. Cox collected it during the Canadian Arctic Expedition 1913-1918(Macoun and Holm 1921, Polunin 1940. Isely (1998) synonymized this taxon (as var. foliolosa (Hook.) Barneby) under var. defl exa, but did so only taking into account material from continental United States, excluding Alaska. Here we follow Cody (1994) and Aiken et al. (2007) and recognize subsp. foliolosa as a discrete taxon in North America. In a pan-Arctic context, Elven et al. (2011) suggested that this taxon may be synonymous with the Russian O. defl exa subsp. dezhnevii (Jurtz.) Jurtz. Further work is needed to clarify the statuses of these taxa, but the Russian name would have priority if these taxa were synonymized.
Specimens examined. Canada. Northwest Territories: Inuvik Region, Victoria Island, River valley at N head of Minto Inlet, ca. 3 km from inlet, 71°33'46.7"N, 115°22'45.1"W, 24 m, 23 July 2010, Gillespie, Saarela, Doubt, Bull & Sokoloff 10129 (CAN-598345). Lentibulariaceae Pinguicula vulgaris L. Fig. 15 Common name. Butterwort Distribution. Nearly circumboreal-polar Comments. Th is species was fi rst reported from the western Arctic Islands by Th annheiser et al. (2001; no voucher collection located for confi rmation) at Johansen Bay on Victoria Island (they incorrectly considered their record as the fi rst for the whole CAA). We collected this species at Johansen Bay and Clauston Bay on southwestern Victoria Island and from three sites in the Minto Inlet area on northwestern Victoria Island, extending the northern range of this low Arctic species. On Victoria Island the species was sometimes locally common and populations were scattered mostly in moist to wet meadows on river fl ats. Two nearby populations were discovered in rocky tundra on the top of a plateau south of Minto Inlet; the larger population (Gillespie et al. 9967) comprised about 50 plants scattered in a moist depression in a boulder fi eld adjacent to an Eriophorum meadow above the head of a canyon. Th e species was previously known in the CAA based on four collections from southeastern Baffi n Island (Porsild 1957, Porsild and Cody 1980, Aiken et al. 2007). We collected it at six sites there, in the vicinity of Kimmirut (where previously known) and from fi ve sites along the Soper River (one previous collection known).
We encountered a single population of U. ochroleuca on southern Baffi n Island, forming a dense fl oating mat along the bottom of a shallow muddy pond in a wet sedge meadow comprised of Carex bigelowii Torr. ex Schwein., C. chordorrhiza Ehrh. ex L. f., C. holostoma, Betula glandulosa, Arctagrostis latifolia subsp. latifolia, Eriophorum vaginatum L. and E. scheuchzeri subsp. scheuchzeri. Th is population was uniformly sterile-no conspicuous emergent fl owers were seen. Th is pattern is seen in many species of Utricularia above the treeline (Porsild and Cody 1980), particularly U. ochroleuca (G. Crow, pers. comm. 2014). Th is species may be more common in the low Arctic than herbarium records suggest and should be looked for carefully.
Specimens examined. Canada. Nunavut: Qikiqtaaluk Region, Baffi n Island, Katannilik Territorial Park Reserve, Soper River, 18.5 km downstream (S) of its confl uence with the Livingstone River, 1.5 km S of Emergency Cabin #8, E bank of river, Primulaceae Primula egaliksensis Wormsk. Fig. 17 Common name. Greenland primrose Distribution. Arctic-alpine amphi-Beringia-North America Comments. Our collections are the fi rst for this species in the CAA. Th is species commonly occurs along lakeshores and riverbeds in tundra and alpine regions of Canada, Greenland and the United States Cody 1980, Kelso 2009), and is known from both Ungava Bay to the south and Greenland to the west of southeastern Baffi n Island where our collections were made. One population collected was found in a moist mossy depression among rocks in a disturbed site near the Kimmirut boat landing on Soper Lake, associated with Chamerion latifolium, Bistorta vivipara and Cardamine pratensis subsp. angustifolia (Hook.) O.E. Schultz. Th e second population was on moist mossy ground among rocky outcrops on a small island, with Leymus mollis, Juncus arcticus, Dupontia fi sheri, Puccinellia phryganodes, Potentilla anserina subsp. egedei (Wormsk. ex Hornem.) Hiitonen and Saxifraga caespitosa L. Similar in size and appearance to P. stricta Hornem., a largely sympatric species that is found in the CAA on Banks Island and Victoria Island, P. egaliksensis is distinguished by its non-farinose fl owering stem (versus farinose at least at the apex), abruptly petiolate leaves, and calyx base that is less prominently saccate and never auriculate (Kelso 2009, Saarela et al. 2013a (Cody et al. 1988, Elven andMurray 2008). All three species were previously treated within Ranunculus L. (Porsild 1957, Porsild and Cody 1980, Cody et al. 1988, Whittemore 1997, Aiken et al. 2007), but they diff er both genetically and morphologically (presence of thick white underground stems, fragrant fl owers, three sepals, spongy tissue in achene) from other members of the genus (Hörandl et al. 2005). Coptidium × spitsbergense, also known from Svalbard and the Russian Arctic, was fi rst recorded in North America by Cody et al. (1988) from one site in southern mainland Nunavut, and four sites in northwestern Arctic Quebec. Th e hybrid is most similar in habit and leaf morphology to C. pallasii, but diff ers in its smaller, pale yellow fl owers. Th e taxon was not treated by Whittemore (1997) for North America.
Coptidium × spitsbergense was found at two sites in the Soper River valley growing in sedge meadows, in wet moss adjacent to ponds. Associates at the fi rst site (Saarela et al. 2194) include Carex bigelowii and Salix arctophila, at the second site Betula glandulosa, Empetrum nigrum, Eriophorum angustifolium, E. scheuchzeri, Rhododendron tomentosum subsp. decumbens, Carex spp. and Salix sp. Only one parent, C. lapponicum, was found nearby at the Saarela et al. 2419 site (parents were not looked for at the other site), growing scattered in moist mossy tundra. Th e other parent, C. pallasii, has not been collected in the Soper River valley and was not observed during our fi eldwork there, but one older collection is known from the vicinity of Kimmirut (Polunin 1173, CAN;Aiken et al. 2007). Elsewhere the hybrid species is also often found in the absence of one (usually C. pallasii) or even both parents. In Svalbard it is more common than either parent and occurs in large stands usually in the absence of one or both parents (Elven and Murray 2008, http://svalbardfl ora.no/). Cody et al. (1988) recorded C. lapponicum as present at all fi ve sites in Canada, and C. pallasii as present at only two sites, both in northern Quebec.
Th roughout its range fruiting specimens have not been observed. Plants are assumed to be spread mainly by bird dispersal of stem-shoot fragments Murray 2008, Elven et al. 2011). However, Cody et al. (1988) considered there to be no evidence for long distance dispersal and suggested that separate hybridization events occurred at each locality sometime in the past.

Salix arctophila Cockerell ex A. Heller
Common name. Northern willow Distribution. Arctic North America Comments. Th is is the fi rst record of this species for the western CAA. Th is sub-Arctic-low Arctic species is distributed from northeastern Alaska to Greenland and south to Maine in the alpine zone (Argus 2007). Its range on the Northwest Territories mainland extends to the coast immediately adjacent to where we collected it at Oterkvik Point Cody 1980, Argus 2007). Previous collections in the Arctic Islands have only been made on Baffi n Island and Southampton Island in the eastern CAA (Aiken et al. 2007).

Salix fuscescens Andersson
Common name. Alaska bog willow Distribution. Arctic Asia (NE)-amphi-Beringia-North America Comments. Our collections are the fi rst records for the eastern CAA. Aiken et al. (2007) reported the species in the CAA from a single collection on Victoria Island (Lambert s.n., CAN-52349). Argus (2007) mapped the species as occurring in the low Arctic from Alaska to western Hudson Bay, including southern Victoria Island, King William Island and the lower Boothia Peninsula. Our collections represent an eastern range extension of some 900 km for the species, with respect to the map in Argus (2007).

Common name. Eschscholtz's saxifrage
Distribution. Amphi-Beringia Comments: Collected on Bathurst Island by S. Edlund in 1975, this is only the second collection of this species from the CAA, and the fi rst record from Nunavut. Edlund's collection was shelved in the backlog of the National Herbarium of Canada for nearly 40 years, and was only recently uncovered. However, its signifi cance as a new record was noted on the newsprint accompanying the specimen, indicating its importance was apparent to the collector.
Th ough long known from the alpine tundra of northern Yukon and Alaska (Cody 2000), the 1968 collection on Prince Patrick Island (mapped in Cody 1980 andAiken et al. 2007)-the fi rst record for the Arctic Islands-extended the range of this species northeastwards by over 1000 km. Th e second collection on Bathurst Island pushes this species a further 500 km east in the CAA. Th e apparent gaps in this species distribution may be explained by its habit: when not in fl ower, it can resemble either the very common Saxifraga oppositifolia L. or a lichen (Aiken et al. 2007); either scenario could account for the paucity of collections from the CAA. Distribution. Arctic amphi-Beringia-North America Comments. Th is collection (det. R. Elven and L.J. Gillespie) represents the fi rst record of S. rivularis L. as currently circumscribed from the western CAA and the fi rst record of S. rivularis subsp. arctolitoralis from the CAA. Porsild (1957) and Porsild and Cody (1980) previously treated the species in a broader sense and included plants now treated under S. hyperborea R.Br., a circum-Arctic species (all collections of S. rivularis s.l. mapped by them from the western Arctic Islands are now considered S. hyperborea). As treated by Aiken et al. (2007), S. rivularis is restricted to the eastern CAA, while S. hyperborea is widespread across the CAA; the two species are easily distinguished by the presence of stolons only in S. rivularis. Our collection fi lls in a distribution gap in the widely disjunct amphi-Atlantic-amphi-Beringian distribution of S. rivularis.
Two subspecies have recently been recognized in S. rivularis: subsp. rivularis with an amphi-Atlantic distribution (and widespread in the eastern CAA) and subsp. arctolitoralis with an amphi-Beringian distribution (Jørgensen et al. 2006, Brouillet and Elvander 2009, Elven et al. 2011). Jørgensen et al. (2006, Aiken et al. (2007) and Brouillet and Elvander (2009) considered subsp. arctolitoralis as present in Alaska, but not known from Canada. More recently, Westergaard et al. (2010) presented molecular evidence for the presence of subsp. arctolitoralis on southeastern Baffi n Island and Greenland, suggesting long distance dispersal from Beringia in the post-glacial period. Elven et al. (2011) consider subsp. arctolitoralis as present also in the Yukon and the Mackenzie Delta area of the Northwest Territories and mention that there are also plants from Hudson Bay and northern Quebec and Labrador conforming in both DNA and morphology to the subspecies. Th e two subspecies may be distinguished by the following key (adapted from Jørgensen et al. 2006 andElvander 2009

CAN accession number
Taxon, collector and collector no. URL