Flora of the Canadian Arctic Archipelago
| Flora of the Canadian Arctic Archipelago | |
English: Polar grass, arctic grass,
French: Arctagrostide à larges feuilles,
Inuktitut: Iviit, ivisuka, ivitsuskaka.
Poaceae, Grass family.
Published in Ledeb., Fl. Ross. 4: 434. 1852.
Type: Canada. Melville Island, W.E. Parry, 1819–1820. Holotype: BM. Two fragments: LE.
Synonymy. Colpodium latifolium R. Br., Chlor. Melvill. 28. 1823.
Arctagrostis latifolia var. longiglumis Polunin, Bull. Natl. Mus. Canada 92 (Biol. Ser. 24): 48. 1940. Type: Canada. Nunavut: Baffin Island, Foxe Island, Nettilling Lake, 24 Aug. 1925. J.D. Soper 125636. (Holotype: CAN! Cotype: BM!).
Arctagrosits latifolia subsp. nahanniensis A.E. Porsild, Bull. Natl. Mus. Canada 171 (Biol. Ser. 64): 120. 1961. Type: Canada. N.W.T.: Mackenzie Mountains, Hole-in-wall Lake, lake shore, in sand, elev. 3800 ft., July 18, 1960. E.W. Arnold 121. (Holotype: CAN!).
Arctagrostis latifolia f. aristata Holmb., in Hartmans Handb. 1 Skand. Fl rev. 141. 1922.
Vegetative morphology. Plants 10–95 cm high; perennial herbs. Only fibrous roots present. Ground level or underground stems horizontal; rhizomatous; elongate, or compact; 2–3 mm wide. Ground level or underground stems scales present; surfaces smooth; 8–30 mm long; glabrous. Aerial stems erect. Leaves present; distributed along the stems; alternate; marcescent. Petioles absent. Sheaths present; with the margins fused only in the lower part; with trichomes; scabrous (seen at magnification 40? on flag leaf sheath; uppermost culm sheath longer than the blade); sheath collars present. Ligules present; 2.5–5 mm long; membranous; glabrous; transversely oblong. Ligule apices obtuse (broadly); erose, or lacerate. Leaves grass-like. Blades 6–80 mm long, 2–4 mm wide (when flat), appressed to the stem or spreading, rolled in bud, linear, flat, veins parallel, midvein similar in size to other veins in the leaf (mid leaf). Blade adaxial surface scabrous. Blade abaxial surface scabrous.
Reproductive morphology. Flowering stems circular or oval in cross section. Flowering stems with leaves; culm nodes becoming exposed (lower sheaths); culm nodes number visible 0–3. Inflorescences paniculate; dense (in plants growing in cold habitats), or diffuse (branches spreading and inflorescence becoming stiffly pyramidal, when plants grow at warmer sites); linear, or lanceolate, or pyramidal (particularly at anthesis, or in warmer habitats); 2.5–10(–17) cm long; 8–26 mm wide. Inflorescences main axis glabrous. Number of inflorescence branches at lowest node 5 (or more). Inflorescence primary branches 5–40(–65) mm long; scabrous; with appressed secondary branches (usually), or with spreading secondary branches (in warmer habitats). Spikelets disarticulating above the glumes; oblong; (3–)4–6 mm long; 1.3–2.4 mm wide. Florets per spikelet 1 (rarely 2). Two glumes present (unequal.). First glume 0.8–0.9 × the length of the second glume; 0.65–0.85 × spikelet length; 1.8–4.3 mm long; lanceolate; glabrous; margins glabrous; veins 1(–3); apex acute. Second glume 0.4–0.9 × as long as the spikelet; shorter than the lowest floret (usually 1 mm or more shorter than the lemma); 2.3–5 mm long. Second glume lanceolate. Second glume glabrous; veins (1–)3. Rachilla extending beyond the uppermost floret (usually, rarely terminating in a well-formed or a vestigial floret). Callus differentiated; hairs shorter than the floret. Lemma lanceolate; 3–6 mm long; keeled (thinner in texture towards the apex); surface dull; surface sparsely scabrous (similar to lemma surface); surface with trichomes on and between the veins; veins 3–5 (lateral veins obscure, not reaching to the apex); apex acute; apex entire; apex glabrous; awnless. Palea well developed; 3.7–5.5 mm long; veins scabrous (similar to the lemma in length, with a single keel at one prominent vein and the second vein faint). Flowers bilaterally symmetrical (zygomorphic); bisexual. Perianth represented by lodicules. Sepals modified (but not a pappus). Stamens 3. Anthers purple becoming yellow, or yellow; 1.8–4 mm long. Ovary superior; carpels 3; syncarpous. Ovaries glabrous. Styles 2. Placentation basal. Ovules per ovary 1. Fruit sessile; dry; a caryopsis; 1.7–3 mm long; indehiscent. Seeds 1.
Chromosome information. 2n = 28, 42, 56, and 62 (Five voucher specimens of A. latifolia with 2n = 28 were annotated by S. Aiken at LE in Feb. 1999.).
2n (4x) = 28. Vouchers in LE examined by Aiken; Mitchell (1992, southern Alaska);
2n (6x) = 42. Sokolovskaya (1955, 'suppressed' by Löve and Löve 1975); Mitchell (1992, passes through the Brooks Range, Alaska);
2n (8x) = 56. Holmen (1952, Greenland); Jørgensen et al. (1958, Greenland); Bowden (1960a, North America); Sokolovskaya and Strelkova (1960); Löve and Löve (1964a); Löve and Ritchie (1966, northern Canada); Hedberg (1967, northern Canada); Zhukova (1967a, northeastern Asia); Johnson and Packer (1968, northwestern Alaska); Sokolovskaya (1968, northeastern Asia, Koryak); Packer and McPherson (1974, northern Alaska); Krogulevich (1976a, northern Siberia; 1978, southern and northern Siberia); Zhukova and Petrovsky (1976, western Chukotka, 1987b, northeastern Asia, 2n = 57); Zhukova et al. (1977, northeastern Asia); Zhukova (1982, northeastern Asia); Mitchell (1992, northern Alaska);
2n (about 9x) = 62. Flovik (1938, Svalbard, a count 'suppressed' by Löve and Löve 1975).
Ploidy levels recorded 4x/6x/8x/9x.
Taxon as an environmental indicator. Culm height in this species appears to be strongly correlated with environmental factors, particularly temperature. Plants growing on the sheltered or sunny side of a rocky outcrop may be conspicuously taller and have more open inflorescences than plants growing in a colder, northfacing adjacent microhabitat. The extent to which the inflorescence opens becomes also appears to be related to environmental factors. Plants with larger more spreading inflorescences occur in known thermal oases, for example, an oasis that has been documented by J. Jacobs, Dept. of Geography, Memorial University, at Burwash Bay, Nettilling Lake, Baffin Island, personal communication, 1986.
Ecology and habitat. Substrates: wet meadows, hummocks, around the margins of ponds, marshes, along streams (and in old stream beds), river terraces (channels, floodplains, or braided flats), tundra, slopes, ridges; imperfectly drained moist areas, seepage slopes, solifluction slopes, dry, moderately well-drained areas; rocks, gravel, sand, silt, clay (sometimes on slumping slopes), till, moss; with low organic content, peat (rarely in peat bogs); calcareous. Occurring in a wide range of habitats and exhibiting considerable phenotypic plasticity that appears to reflect the warmth and nutrients available in an environment. This is a circumpolar species that in the Canadian Arctic Islands is most commonly found in the warmer sectors where it is a regular, but generally not abundant, constituent of moderately to imperfectly drained tundra communities, but it is rarely a primary coloniser.
North American distribution. Alaska, Yukon, Northwest Territories Islands, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec. Range in the Canadian Arctic Archipelago widespread. Common. Arctic. Arctic islands: Baffin, Devon, Ellesmere, Axel Heiberg, Parry islands (Bathurst, Eglington Melville, Prince Patrick), Cornwallis, Banks, Victoria, Prince of Wales, Somerset, King William, Southampton, Coats (Bylot, Mill, Nottingham, Prince Charles Ottawa, Salisbury Islands, Boothia and Melville peninsulas).
Northern hemisphere distribution. Circumpolar, or circumboreal. Northern Fennoscandian, Kanin–Pechora, Svalbard – Franz Joseph Land, Polar Ural – Novaya Zemlya, Yamal–Gydan, Taimyr – Severnaya Zemlya, Anabar–Olenyok, Kharaulakh, Yana–Kolyma, West Chukotka, Wrangel Island, South Chukotka, East Chukotka, West Alaska, North Alaska – Yukon, Central Canada, Labrador – Hudson Bay, Ellesmere Land – Peary Land, West Greenland, East Greenland.
General notes. Porsild (1964) ignored var. longiglumis Polunin, which was described from a thermal oasis on Baffin Island. Polunin (1940) described the species as "an atrocious typus polymorphus". Aiken and Lefkovitch (1990) studied the genus, documented considerable phenotypic plasticity within the species, and found only subsp. latifolia on the Arctic Archipelago, although subsp. arundinacea (Trin.) Tzvelev occurs nearby on the North American continent. No reason for recognising var. longiglumis was found.
Ovenden (1986) found that Arctagrostis latifolia and Puccinellia borealis were common on the lake bed of Illisarvik, the site of a thermokarst lake that was artificially drained in August 1978.
The nematode Anguina agrostis Steinbuck infects spikelets and causes the ovaries to enlarge and become dark purple (Mulvey 1963). Other parts of the infected spikelet become atypical. Specimens with this infection are conspicuous and have been annotated as forma prolifera or forma vivipara, but these names have no taxonomic validity.
Illustrations. • Habitat. Plants less than 20 cm high with compact young inflorescences. Nunavut, Ellesmere Island, Scoresby Bay, on small island in the floodplain of a stream on wet, calcareous silt. 79�53'N, 71�33'W. Aiken 98–013. Photograph by Mollie MacCormac. Scale bar in cm. • Close-up of pre-anthesis inflorescences. Inflorescence very narrow prior to anthesis. Spikelets appressed. Nunavut, Ellesmere Island, Scoresby Bay, 79�53'N, 71�33'W. Aiken 98–013. Photograph by Mollie MacCormac. • Close-up of inflorescence. Plant with compact, reddish inflorescence composed of branches with few spikelets. Uppermost leaf sheath longer than the blade. Aiken 98–013. CAN. Scale bar in cm. • Close-up of inflorescence. Inflorescence at anthesis, with purple anthers approximately 3 mm long, and white, feathery stigmas. Note that the spikelets have a single floret and the second glume is at least 1 mm shorter than the lemma. The palea is almost as long as the lemma and folded so that it looks similar to the lemma. Nunavut, Baffin Island, Iqaluit. Aiken 94–022. CAN. Photograph by K. Clarkin. • Close-up of inflorescence. Portion of panicle with short branches with 10–15 spikelets. Norway, Finnmark, Vardoe, Langbunes. July, 1981. Voucher at TROM. Photograph by R. Elven. • Holotype. Holotype specimen of Arctagrostis latifolia. Nunavut, Melville Island. 1819–1820. W.E. Parry. Holotype: BM. Photograph by L. Consaul. • 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.
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