Trisetum spicatum (L.) K. Ricther
Poaceae, grass family.
Pl. Eur. 1: 59. 1890
Aira spicata L. Sp. Pl. 64. 1753. Trisetum alaskanum Nash, Bull. New York Bot. Gard. 2: 155. 1901. Trisetum spicatum var. alaskanum Malte ex Louis-Marie, Rhodora 30: 239. 1928. Trisetum spicatum subsp. alaskanum Hultén, Svensk Bot. Tidskr. 53: 210. 1959.
Type: Described from Northern Sweden, Lapland (Tzvelev 1976).
Avena mollis Michx., Fl. Bor. Amer. 1: 72. 1803. Trisetum spicatum var. molle (Michx.) Beal, Grasses N. Amer. 2: 377. 1896. 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!)
Vegetative morphology. Plants perennial herbs; 10–40 cm high; caespitose. Ground-level or under-ground stems not developed horizontally or vertically. Aerial stems erect; circular or oval in cross-section; densely hairy. Leaves in a basal tuft; alternate; marcescent. Petioles absent. Sheaths with the margins fused only in the lower part; with trichomes; hirsute; collars present. Ligules present; 0.8–3 mm long; a fringed membrane; hairy; transversely oblong; apices acute to truncate; erose, or lacerate. Blades 17–85 mm long; 1.2–2.2 mm wide (when flat). Blades 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. Blades adaxial surface hairy. Blades abaxial surface hairy (softly villous, or puberulent).
Reproductive morphology. Flowering stems present. Flowering culm nodes not exposed. Inflorescence paniculate (dense, cylindrical or ovoid, often deep purple brown, with prominent twisted, geniculate awns); dense; linear; 2–5 cm long; 5–13 mm wide; 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 pedicellate (pedicels are very short); disarticulating above the glumes; laterally compressed; lanceolate, or ovate; 3.9–6.6(–7.5) mm long; 1.5–3 mm wide. Florets per spikelet 2–3. 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 (very 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; lanceolate; 3.4–5.5 mm long; glabrous, or with trichomes (scaberulous on keel); veins 3. Rachilla internode 0.8–1.2 mm long; hairy. Rachilla not pronounced between the florets; extending beyond the uppermost floret. Callus differentiated; hairs 0.1–0.3 mm long; hairs shorter than the floret. Lemma (3.5–)4.5–5.3 mm long; lanceolate; keeled (slightly); surface dull; surface sparsely scabrous; veins 3. Lemma apex acute; entire; 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). Palea well developed; 3.7–4.2 mm long; with scabrous veins. Perianth reduced to lodicules. Stamens 3. Anthers (0.6–)1–1.2 mm long. Gynoecia superior. Carpels syncarpous; 3. Styles 2. Ovules 1. Fruit sessile. Fruit dry; a caryopsis; indehiscent. Fruit 2.3–2.7 mm long. Seeds 1.
Chromosome information. 2n = 28. 28 (4x). -
spicatum' s.s.
Flovik (1938, 1940 Svalbard); Löve and
Löve (1944b northern Europe,' 1956b Iceland); Böcher and Larsen
(1950 Greenland); Holmen (1952 Greenland); Löve (1954b Iceland);
Sokolovskaya (1955, 1960b north eastern Asia Sakhalin); 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 etc.); Dalgaard (1988 western Greenland).
'alaskanum'
Sokolovskaya and Probatova
(1975')
2n = 28, 42, the latter probably a 'molle'
entity,Tateoka (1978 Japan, 'alaskanum', )
spicatum'
s.l.
Böcher (1959); Morrison (1959a, 1959b); Bowden (1960b Alaska,
three counts); Sokolovskaya and Strelkova (1960); Zhukova (1965a eastern
Chukotka, 1967, 1969, 1973 north eastern Asia); ; Krogulevich (1976 northern
Siberia); Zhukova and Petrovsky (1976, 1980 western Chukotka); Reeder (1977
western North America); Zhukova et al. (1977a north eastern Asia); Zhukova (1980
southern Chukotka, 1982 north eastern Asia); Petrovsky and Zhukova (1981 Wrangel
Island); Wade (1986). Ploidy levels recorded 4x.
Distribution. Northern hemisphere distribution: circumpolar. Arctic, or alpine. Range in the Canadian Arctic Archipelago widespread. Arctic Islands: Baffin, Devon, Ellesmere, Axel Heiberg, Parry Islands, Banks, Victoria, Prince of Wales, Somerset, Southampton, Coats.
Ecology and habitat. Substrates: river terraces, lake shores, tundra, slopes, ridges, cliffs, seashores (but above tidal influence); on seepage slopes, or on solifluction slopes, or dry, or moderately well drained areas; acidic, or calcareous, or nitrophilous; rocks (granite, gneiss, or sandstone scree), gravel, sand, silt, clay, till. Habitats: Commonly found in well-drained, silty, sandy, or gravely 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.
Taxon as an environmental indicator. This species is an early colonizer 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.
Notes. Hultén (1959) reported on the T. spicatum complex and recognized 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 forth 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.
Illustrations. • Laboratory photograph. Nunavut, Baffin Island, Iqaluit, Aiken, 94–023. (CAN). Photograph taken August 1994, by K. Clarkin. • Close-up of inflorescence. Nunavut, Baffin Island, Iqaluit, Aiken 94–023. (CAN). Laboratory photograph showing close-up of inflorescence with curved awns extending beyond the compact spikelets. Photograph taken August 1994, by K. Clarkin. • 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). • Distribution map.
Cite this publication as: ‘S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, L.J. Gillespie, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, A.K. Brysting and H. Solstad. 1999 onwards. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 29th April 2003. http://www.mun.ca/biology/delta/arcticf/’. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993, 1995, 2000) should also be cited (see References).
