Hordeum jubatum L. subsp. jubatum

Gillespie, Lynn J., Saarela, Jeffery M., Sokoloff, Paul C. & Bull, Roger D., 2015, New vascular plant records for the Canadian Arctic Archipelago, PhytoKeys 52, pp. 23-79 : 37

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 differ 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 and von Bothmer 1994). Bowden (1962) considered subsp. intermedium to be a hybrid between Hordeum jubatum s.s. and Hordeum brachyantherum Nevski, but to our knowledge this hypothesis has not been tested with molecular data. Some authors treat subsp. intermedium as a separate species, Hordeum 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 ( Baden and 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, Hordeum jubatum subsp. intermedium has been recorded from Hood River, Nunavut (Anderson 473 in 1915, CAN-39857 & CAN-514373; Macoun and Holm 1921, Bowden 1962) and from Tuktoyaktuk, Northwest Territories (Aiken & McLachlan 87-221 in 1987, CAN-530893). Two records of Hordeum 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, Baffin 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). These three specimens were not previously determined to subspecies. The 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. The 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. There is also a 2003 collection from a separate locality in nearby Iqaluit (across from Joamie Ilinniarvik School, Mallory s. n., CAN-585777). The 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 Hordeum jubatum subsp. jubatum in the community of Kimmirut in 2012, adding a second area of occurrence for the species on Baffin 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., Poa 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. The 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.).

Specimens examined.

Canada. Nunavut: Qikiqtaaluk Region, Baffin Island, Kimmirut, rocky sandy slope between Northern Store and coast, 62°50'57"N, 69°52'12"W, 68 m, 22 July 2012, Saarela, Gillespie, Sokoloff & Bull 2737 (ALA, ALTA, CAN-601368); Qikiqtaaluk Region, Baffin Island, Kimmirut, S end of hamlet, below garbage dump and above high tide line at coast, 62°50'26"N, 69°52'20"W, 68 m, 22 July 2012, Saarela, Gillespie, Sokoloff & Bull 2755 (CAN-601369, O, US).