Flora of the Canadian Arctic Archipelago


S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, L.J. Gillespie, A.K. Brysting, H. Solstad, and J.G. Harris

Poa alpina L.

English: Alpine bluegrass,

French: Pâturin alpin,

Inuktitut: Iviit, ivisuka, ivitsuskaka.

Poaceae, Grass family.

Published in Sp. Pl. 67. 1753.

Type: Described from northern and central European mountains, selected by Soreng in Cafferty et al., Taxon 49: 254. 2000. Lectotype: LINN 87.2.

Synonymy. Poa pratensis L. var. alpina (L.) Huds., Fl. Anglica, ed. 2. 39. 1778.

Poa alpina var. minor Scribn. ex Beal, Grasses N. Amer. 2: 543. 1896: not Koch, 1837. Type: USA. Montana: Little Belt Mountains., 12 Aug. 1883, Scribner 388.

Poa alpina f. brevifolia Polunin, Can. Field-Nat. 52: 7. 1938.

Vegetative morphology. Plants 10–40 cm high; perennial herbs; caespitose. Only fibrous roots present. Ground level or underground stems absent (base of tillers enclosed by thick mats of accumulated leaf sheaths that persist more than a year; branching of innovations is strictly intravaginal). Aerial stems erect. Leaves mainly basal; alternate; marcescent. Prophylls 10–30 mm long; with scabrous veins (minute trichomes); with pronounced keels (as pronounced as in a 2-keeled palea). Petioles absent. Sheaths present; with the margins fused only in the lower part (lower 1/4); glabrous (or with extremely minute trichomes visible at 40x); sheath collars present. Ligules present; 1–3.7(–5) mm long (basal leaves 1–2(-3) mm; cauline leaves 2–4(-5) mm long); membranous; glabrous; variable. Ligule apices obtuse (cauline leaves), or truncate (basal leaves); entire, or lacerate (cauline leaves). Leaves grass-like. Blades 10–55(–100) mm long (appearing relatively short; the culm leaves, 1 or rarely 2, occur on the lower half of the culm, leaving most of the culm leafless; the culm leaves are relatively short and of nearly uniform width until the abruptly contracted apex), 0.5–1.6 mm wide (when folded, to 4.5 mm when flat), appressed to the stem or spreading, folded in bud, linear, flat or folded, veins parallel, midvein conspicuously larger than the lateral veins, bulliform cells in distinct rows on either side of the midvein. Blade adaxial surface glabrous. Blade abaxial surface glabrous or scabrous (scaberulous on midvein). Blade apices obtuse, or rounded (broad and blunt).

Reproductive morphology. Flowering stems two or more per plant. Flowering stems circular or oval in cross section. Flowering stems with leaves; culm nodes becoming exposed; culm nodes number visible 0–1. Inflorescences paniculate; dense, or diffuse; pyramidal (branches with several spikelets and tending to drop); 2–6 cm long; 10–60 mm wide. Inflorescences main axis glabrous (usually), or scabrous (sparsely, rarely densely, scaberulous). Number of inflorescence branches at lowest node 2 (usually, the lower branches pulvinate in larger specimens). Inflorescence primary branches 3–24 mm long; glabrous, or scabrous (sparsely scaberulous, terete); with spreading secondary branches (divaricate, often drooping). Spikelets disarticulating above the glumes; ovate; 3.9–6.2 mm long; 2.5–4 mm wide (broad, often sub-cordate, at anthesis). Florets per spikelet 3–4. Two glumes present (often half as wide as long.). First glume 0.9–0.95 × the length of the second glume; 0.6–0.7 × spikelet length; 2.6–3.8 mm long; ovate; glabrous, or with trichomes (scabrous on the midvein); margins glabrous; veins (1–)3; apex acute. Second glume 0.4–0.9 × as long as the spikelet; almost as long as, or longer than, the lowest floret; 2.8–4.2(–4.6) mm long. Second glume ovate. Second glume glabrous, or with trichomes (on keel); veins 3. Rachilla not pronounced between the florets; extending beyond the uppermost floret; internode 0.6–1 mm long; internode glabrous. Callus not differentiated. Lemma lanceolate; 3.4–4.2 mm long; keeled (slightly); surface dull; surface hairy; surface with trichomes on and between the veins (densely hairy on the keel and marginal veins, sparsely hairy on surface between the veins. Not webbed at base); veins 5; apex acute; apex entire; awnless. Palea well developed; 2.9–3.6 mm long; veins hairy (hairs longer towards the base of the palea). Flowers bilaterally symmetrical (zygomorphic). Perianth represented by lodicules. Stamens 3. Anthers 1.5–2.3 mm long. Ovary superior; carpels 3; syncarpous. Ovaries glabrous. Styles 2. Placentation basal. Ovules per ovary 1. Fruit sessile; dry; a caryopsis; 1.8–2.2 mm long; indehiscent. Seeds 1.

Chromosome information. 2n = 14, 22–74. These numbers suggest agamospermy.

2n (2x) = 14. Sokolovskaya and Strelkova (1940, 1948b); Müntzing (1948, 1966); Hubbard (1954); Müntzing and Nygren (1955); Nygren (1956a); Milinkovic (1957); Quézel (1957); Conert (1998, central and southern Europe);

2n (3x-10/11x). = 22–74.

2n = 22–74. Löve and Löve (1966a, Iceland);

2n = 28. Böcher and Larsen (1950 northern, Europe or Greenland);

2n = 28, 35. Yurtsev and Zhukova (1978, eastern Chukotak);

2n = 28, 32, 33, 35. Krogulevich (1976a, northern Siberia);

2n = 30–34. Hedberg (1967, northern Canada);

2n = 31–52. Vestre in Engelskjøn (1979, Norway, a total of about 150 counts);

2n = 32–34, 42. Sokolovskaya (1970);

2n = 32. Zhukova and Tikhonova (1973, northeastern Asia);

2n = 33, 34. Yurtsev et al. (1975, eastern Chukotka);

2n = 33, 39. Engelskjøn (1979, Norway);

2n = 33 - about 48. Böcher (1938a);

2n = 33–52. Müntzing (1954, northern Europe including Norway);

2n = 33–46. Moltzau (1958, Norway);

2n = 35. Johnson and Packer (1968, northwestern Alaska);

2n = 39. Lövkvist and Hultgård(1999, southern Sweden);

2n = 42. Sokolovskaya (1955);

2n = 42. Löve (1981b central Canada);

2n = 42. Sokolovskaya and Strelkova (1960);

2n = 42. Bowden (1961, Alaska);

2n = 42. Löve and Ritchie (1966, northern Canada);

2n = 42. Taylor and Brockman (1966, western Canada);

2n = 42. Dalgaard (1989, western Greenland). Numerous more southern counts.

Ploidy levels recorded 2x/3x-10x/11x.

Taxon as an environmental indicator. In the Low Arctic this species may indicate areas where the snow lies late into the season or a mildly alkaline substrate. For example, it was observed to be more common and growing in calcareous clay at Silliman's Fossil Ridge, Frobisher Bay, 63°46'N, 68°59'W, than at Iqaluit where soil taken from near Arctic College had a field pH = 6.8.

Ecology and habitat. Substrates: hummocks, snow patches; calcareous. Usually on snowbeds, often in calcareous soils. An alpine and Low Arctic taxon that occurs only in the southern islands of the Canadian Arctic Archipelago.

North American distribution. Alaska, Yukon, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec, Labrador. Range in the Canadian Arctic Archipelago limited. Uncommon. Low Arctic, alpine. Arctic islands: Baffin, Parry islands (Melville), Southampton, Coats (and Melville Peninsula).

Northern hemisphere distribution. Circumpolar, or circumboreal (with a large gap in northern Asia). Northern Iceland, Northern Fennoscandian, Kanin–Pechora, Svalbard – Franz Joseph Land, Polar Ural – Novaya Zemlya, Yamal–Gydan, Taimyr – Severnaya Zemlya, East Chukotka, West Alaska, North Alaska – Yukon, Central Canada, Labrador – Hudson Bay, West Greenland, East Greenland.

General notes. This taxon is readily distinguished from other Arctic Poa species by its broad leaves that are nearly uniformly wide until they are abruptly contracted at the apex, the build-up of a "thick sock" (or its "booties") of old sheaths at the base of the plant, and by the relatively large spikelets that often seem to cause the branches to droop.

Polunin (1940) commented that no viviparous forms were found in the Canadian Arctic. Porsild (1957, 1964) and Porsild and Cody (1980), however, describe P. alpina as viviparous, particularly in the Canadian Eastern Arctic. Viviparous or vegetatively proliferating specimens substantiating this statement have not been found in CAN or DAO, or recently collected. They are, however, common in northern Europe (R. Elven, personal communication). Viviparous P. alpina is treated as a variety, P. alpina var. vivipara L., by Elven et al. (2003), and as a subspecies by Soreng et al. (2003).

Poa alpina was found to be an early coloniser of oil spills in Alaska (Kershaw and Kershaw 1986).

Illustrations. • Drawing. Note relatively wide and short leaves towards the base of the plant, and relatively large and heavy spikelets. Drawing from Canadian Museum of Nature photo library, S74–1087. • Contrasting two species. G, a tussock of Poa glauca. A, a tussock of Poa alpina that has dried out. Nunavut, Baffin Island, beach at Apex. 19 August, 2006. Aiken. No voucher. • Herbarium specimen. Herbarium specimen showing densely cespitose plant. Inflorescences dense with large spikelets. Nunavut, Baffin Island, Nettilling Lake. Aiken 86–172, C. Campbell, E. Robinson. CAN 518032. • Close-up of inflorescence. Inflorescence with several spikelets on the lower drooping branches. Nunavut, Baffin Island, Iqaluit. 24 July, 2005. Photograph Kathy Thornhill. No voucher. • Arctic Island Distribution.

This publication is available on the internet (posted May 2011) and on CD-ROM (published in 2007). These versions are identical in content, except that the errata page for CD-ROM is accessible on the main index page of the web version.

Recommended citation for the web-based version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. NRC Research Press, National Research Council of Canada, Ottawa. http://nature.ca/aaflora/data, accessed on DATE.

Recommended citation for the CD-ROM version of this publication: Aiken, S.G., Dallwitz, M.J., Consaul, L.L., McJannet, C.L., Boles, R.L., Argus, G.W., Gillett, J.M., Scott, P.J., Elven, R., LeBlanc, M.C., Gillespie, L.J., Brysting, A.K., Solstad, H., and Harris, J.G. 2007. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. [CD-ROM] NRC Research Press, National Research Council of Canada, Ottawa.