Flora of the Canadian Arctic Archipelago

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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

Trisetum spicatum (L.) K. Richter

English: Narrow false-oat,

French: Trisè à épi,

Inuktitut: Ivit iviksugait.

Poaceae, Grass family.

Published in Pl. Eur. 1: 59. 1890.

Type: Sweden: 'Lapland', 1732, selected by Edgar and Connor, New Zealand J. Bot. 36: 556. 1998. Lectotype: LINN 85.7.

Synonymy. Aira spicata L. Sp. Pl. 64. 1753.

Avena mollis Michx., Fl. Bor. Amer. 1: 72. 1803.

Trisetum spicatum var. molle (Michx.) Beal, Grasses N. Amer. 2: 377. 1896.

Trisetum alaskanum Nash, Bull. New York Bot. Gard. 2: 155. 1901.

Trisetum spicatum var. alaskanum (Nash) Malte ex Louis-Marie, Rhodora 30: 239. 1928.

Trisetum spicatum subsp. alaskanum (Nash) Hultén, Svensk Bot. Tidskr. 53: 210. 1959.

Trisetum spicatum var. maidenii (Gand.) Fernald, Rhodora 18:196. 1916.

T. spicatum (L.) K.Richt. var. villosissimum (Lange) Louis-Marie, Rhodora 30: 239. 1928.

Trisetum subspicatum (L.) P.Beauv. var. villosissimum Lange, Consp. Fl. Groenland. 164. 1880, described from Greenland.

Trisetum spicatum var. pilosiglume Fernald, Rhodora 18: 195. 1916. Type: Canada. Newfoundland: Notre Dame Bay, 1911, M.L. Fernald, K.M. Wiegand and E.B. Bartram 4593. (Isotype: CAN!).

T. spicatum (L.) K. Richt. subsp. wrangelense V.V. Petrovsky, Bot. Zhurn. (Moscow & Leningrad) 63: 1263. 1978, described from Wrangel I.

T. wrangelense (V.V. Petrovsky) Prob., Sosud. Rast. Sovet. Dal'nego Vostoka 1: 163. 1985.

Vegetative morphology. Plants 10–40 cm high; perennial herbs; caespitose. Only fibrous roots present. Ground level or underground stems absent. Aerial stems erect. Leaves mainly basal; alternate; marcescent. Petioles absent. Sheaths present; with the margins fused only in the lower part; with trichomes; hirsute; sheath collars present. Ligules present; 0.8–3 mm long; a fringed membrane; hairy; transversely oblong. Ligule apices acute to truncate; erose, or lacerate. Leaves grass-like. Blades 17–85 mm long, 1.2–2.2 mm wide (when flat), appressed to the stem or spreading, rolled in bud (very prominent ribs may lead to margins touching, as with blades folded in bud), linear, flat or involute, veins parallel, midvein similar in size to other veins in the leaf. Blade adaxial surface hairy. Blade abaxial surface hairy (softly villous, or puberulent).

Reproductive morphology. Flowering stems two or more per plant. Flowering stems circular or oval in cross section. Flowering stems culm nodes not exposed. Inflorescences paniculate (dense, cylindrical or ovoid, often deep purple-brown, with prominent twisted, geniculate awns); dense; linear; 2–5 cm long; 5–13 mm wide. Inflorescences main axis hairy (strongly pubescent with long, soft hairs). Number of inflorescence branches at lowest node 3–4. Inflorescence primary branches 0.2–0.8 mm long; scabrous (hairy); with appressed secondary branches, or with spreading secondary branches. Spikelets disarticulating above the glumes; lanceolate, or ovate; 3.9–6.6(–7.5) mm long; 1.5–3 mm wide. Florets per spikelet 2–3. Two glumes present. First glume 0.74–0.85 × the length of the second glume; 0.6–0.7 × spikelet length; 2.5–4.5 mm long; lanceolate; glabrous; margins ciliate (with few and short hairs); veins 1; apex acuminate. Second glume 0.4–0.9 × as long as the spikelet; almost as long as, or longer than, the lowest floret; 3.4–5.5 mm long. Second glume lanceolate. Second glume glabrous, or with trichomes (scaberulous on keel); veins 3. Rachilla not pronounced between the florets; extending beyond the uppermost floret; internode 0.8–1.2 mm long; internode hairy. Callus differentiated; hairs 0.1–0.3 mm long; hairs shorter than the floret. Lemma lanceolate; (3.5–)4.5–5.3 mm long; keeled (slightly); surface dull; surface sparsely scabrous; veins 3; apex acute; apex entire; apex glabrous; awned. Awn arising from below the apex but above the middle (affixed at the upper third or fourth of the lemma, bent and twisted). Awn 2–4 mm long. Palea well developed; 3.7–4.2 mm long; veins scabrous. Flowers bilaterally symmetrical (zygomorphic). Perianth represented by lodicules. Stamens 3. Anthers (0.6–)1–1.2 mm long. Ovary superior; carpels 3; syncarpous. Styles 2. Placentation basal. Ovules per ovary 1. Fruit sessile; dry; a caryopsis; 2.3–2.7 mm long; indehiscent. Seeds 1.

Chromosome information. 2n = 28.

2n (4x) = 28. 'spicatum' s.s.

Flovik (1938, 1940, Svalbard); Löve and Löve (1944b, northern Europe; 1956, Iceland); Böcher and Larsen (1950, Greenland); Holmen (1952, Greenland); Löve (1954b, Iceland); Sokolovskaya (1955, 1960b, northeastern Asia); Jørgensen et al. (1958, Greenland); Mosquin and Hayley (1966, northern Canada); Knaben and Engelskjøn (1967, Norway); Hedberg (1967, northern Canada); Johnson and Packer (1968, northwestern Alaska); Zhukova and Tikhonova (1971, Chukotka); Mulligan and Porsild (1970, Yukon); Packer and McPherson (1974, northern Alaska); Jonsell et al. (1975, northern Norway); Dalgaard (1988, western Greenland).

'alaskanum'

2n = 28, 42, the latter probably a 'molle' entity, Tateoka (1978, Japan, 'alaskanum'), Sokolovskaya and Probatova (1975);

'spicatum' s.l.

2n = 28 and 42. Böcher (1959); Morrison (1959a, 1959b); Bowden (1960b, Alaska, three counts); Sokolovskaya and Strelkova (1960); Zhukova (1965a, eastern Chukotka; 1967, 1969, 1973, northeastern Asia); ; Krogulevich (1976a, northern Siberia); Zhukova and Petrovsky (1976, 1980, western Chukotka); Reeder (1977, western North America); Zhukova et al. (1977, northeastern Asia); Zhukova (1980, southern Chukotka, 1982, northeastern Asia); Petrovsky and Zhukova (1981, Wrangel Island); Wade (1986).

Ploidy levels recorded 4x/6x.

Taxon as an environmental indicator. This species is an early coloniser of disturbed sandy and silty ground. The plants are relatively short and are eventually crowded out of a habitat by taller grass species such as Poa glauca.

Ecology and habitat. Substrates: river terraces, lakeshores, tundra, slopes, ridges, cliffs, seashores (but above tidal influence); seepage slopes, solifluction slopes, dry, moderately well-drained areas (Air Force, Bylot, Mill Islands); rocks (granite, gneiss, or sandstone scree), gravel, sand, silt, clay, till; acidic, or calcareous, or nitrophilous. Commonly found in well-drained, silty, sandy, or gravelly soils, often at the edge of disturbed terrain, such as the edge of solifluction lobes, thaw-flow slides, and around disturbed construction sites in settlements.

North American distribution. Alaska, Yukon, Northwest Territories Islands, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec, Labrador. Range in the Canadian Arctic Archipelago widespread. Common. Arctic, alpine. Arctic islands: Baffin, Devon, Ellesmere, Axel Heiberg, Parry islands (Bathurst, Melville, Prince Patrick), Banks, Victoria, Prince of Wales, Somerset, Southampton, Coats.

Northern hemisphere distribution. Circumpolar, or circumboreal (arctic-alpine, and trans-tropical and bipolar). Northern Iceland, 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. Hultén (1959b) reported on the T. spicatum complex and recognised several varieties, stating that plants in the High Arctic conform closely to subsp. spicatum in having dense spike-like inflorescences and a violet colour zone on the glumes and lemmas, while their margins are brown. The culm is strongly pubescent with long, soft, and (except at the top) downward pointing hairs. The panicle branches are pubescent as well as the sheaths, and the awn is affixed at the upper third or fourth of the lemma and bent and twisted. The flowers considerably overtop the glumes. Randall and Hilu (1986) studied T. spicatum throughout its North American distribution and concluded that the data for 33 morphological characters revealed extreme variation within the species and did not support the recognition of infraspecific taxa or the elevation of the hexaploids to specific rank.

Elven et al. (2003) considered this a difficult case where "the status of the different entities described has varied among authors from species through subspecies, variety, and forma to nothing." In addition to the recent work by Randall and Hilu (1986), Syst. Bot. 11: 567–578, we should also consult some previous treatments, e.g., that of Jonsell (1975), Sv. Bot. Tidskr. 69. "There is a contrast between the homogeneity in the material from [mainland Europe] and the High Arctic and the heterogeneity in that from the Beringian area, western (Cordilleran) North America, northeastern North America, southern Greenland, and Iceland. From a European viewpoint it is difficult to neglect this difference entirely; some taxonomy should be involved" (Elven et al. 2003).

Hultén (1959b) reported on the T. spicatum complex and recognised [two subspecies and] several varieties [for the Arctic], stating that plants in the High Arctic conform closely to subsp. spicatum in having dense spike-like inflorescences and a violet colour zone on the glumes and lemmas, while their margins are brown. The culm is strongly pubescent with long, soft, and (except at the top) downward pointing hairs. The panicle branches are pubescent as well as the sheaths, and the awn is affixed at the upper third or fourth of the lemma and bent and twisted. The flowers considerably overtop the glumes. Randall and Hilu (1986) studied T. spicatum throughout its North American distribution and concluded that the data for 33 morphological characters revealed extreme variation within the species and did not support the recognition of infraspecific taxa or the elevation of the hexaploids to specific rank [molle/triflorum] (Aiken).

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

Illustrations. • Habitat: Cape Dorset. Grasses growing on disturbed ground. Note the deep purple spikes. Nunavut, Baffin Island, Cape Dorset. 2 August, 2005. Aiken. No voucher. • Habitat. Isolated clump of lush plants nearly 30 cm high, growing in the shelter of a cluster of rocks that may have been a meat cache (N. Hallendy). Nunavut, Baffin Island, Cape Dorset, south side of island. 3 August, 2005. Aiken. No voucher. • Inflorescence at anthesis. Spike-like panicle at anthesis with straight awns and small anthers showing in open single flowered spikelets. Nunavut, Baffin Island, Iqaluit. July 19, 2004. No voucher. • Isotype, var. pilosiglume. Trisetum spicatum var. pilosiglume. Canada. Newfoundland, Notre Dame Bay, 1911, M.L. Fernald, K.M. Wiegand and E.B. Bartram 4593. (Isotype: CAN). • 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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