Deschampsia brevifolia R. Br.
Arctic hairgrass.
Poaceae, grass family.
D. brevifolia R. Br. in Chlor. Melvill. 33. 1823.
D. cespitosa subspecies brevifolia (R.Br. Tzvelev in Tolmachev, Fl. Sev. Vost. Europ. Chasti SSSR, 1: 141. 1974
Type: Canada. Melville Island, 1819–1820, W. E. Parry. (Holotype: K; two Isotypes: LE (Tzvelev 1976); Topotype: DAO!).
Vegetative morphology. Plants perennial herbs; caespitose. Ground-level or under-ground stems not developed horizontally or vertically. Aerial stems erect; circular or oval in cross-section; glabrous. Leaves in a basal tuft; alternate; simple; marcescent. Petioles absent. Sheaths with the margins fused only in the lower part; glabrous; collars present. Ligules present; 1.3–3.1(–5) mm long; membranous; glabrous; ovate-oblong; apices acuminate, or acute; entire. Blades 5–30(–65) mm long; 0.3–0.8 mm wide (rolled), or 0.5–2.5 mm wide (when flat). Blades appressed to the stem, or spreading; rolled in bud; linear; flat (rarely), or folded, or involute; veins parallel; midvein similar in size to other veins in the leaf. Blades adaxial surface glabrous, or scabrous, or hairy (with sparse minute trichomes). Blades abaxial surface glabrous.
Reproductive morphology. Flowering stems present. Flowering stems hairy. Flowering culm nodes not exposed, or becoming exposed; number visible 0–2. Inflorescence paniculate; dense, or diffuse (occasionally); lanceolate, or ovate (compact or spreading to pyrimidal); 1.5–10(–12) cm long; 5–20(–110) mm wide; main axis glabrous, or scabrous. Number of inflorescence branches at lowest node 3–5. Inflorescence primary branches 1–36(–60) mm long; glabrous, or scabrous; with appressed secondary branches, or with spreading secondary branches (less commonly). Spikelets pedicellate; disarticulating above the glumes; laterally compressed; ovate to obovate; 2.3–5(–6) mm long; 1.4–4 mm wide. Florets per spikelet 2(–3). First glume 0.9–1.2 × the length of the second glume; 0.8–1 × spikelet length; 2.7–4 mm long; lanceolate; glabrous; margins glabrous; veins 1; apex acuminate, or acute. Second glume as long, or longer than the spikelet; almost as long as, or longer than, the lowest floret; lanceolate, or ovate; 3–4(–5.4) mm long; glabrous; veins 3. Rachilla internode 0.5–1.6 mm long. Rachilla extending beyond the uppermost floret. Callus differentiated; hairs 0.3–1.5 mm long; hairs shorter than the floret. Lemma 2.8–4 mm long; oblong, or lanceolate; keeled; lemma not strongly incurved; surface shiny; veins 5 (lateral veins faint). Lemma apex acute, or rounded, or truncate; erose, or lacerate; glabrous; awned. Awn arising from the middle or below (rarely higher up); 1–2.2(–3.5) mm long. Palea well developed; 2.4–3.3(–5) mm long; with scabrous veins (trichomes sparse). Perianth present. Calyx absent. Petals absent. Stamens 3. Anthers 1.5–2.5 mm long. Gynoecia superior. Carpels syncarpous; 3. Styles 1; partially fused. Ovules 1. Fruit sessile. Fruit dry; a caryopsis; elongate-cylindrical; indehiscent. Fruit 2.3–3 mm long. Seeds 1.
Chromosome information. 2n = 26, 27, and 28. 26
(2x). - Holmen (1952 Greenland); Jørgensen et al. (1958
Greenland); Bowden (1960b, 1961 northern Canada); Hedberg (1967 northern
Canada); Knaben (1968 central Alaska); Mulligan and Porsild (1969b Yukon);
Zhukova and Tikhonova (1973 Chukotka).
(2) 52 (4x). - Krogulevich
(1986 northern Siberia, Putorana); Petrovsky and Zhukova (1981 Wrangel Island).
Distribution. Northern hemisphere distribution: Greenland, Canada. Arctic Islands: Baffin, Ellesmere, Axel Heiberg, Parry Islands, Cornwallis, Banks, Victoria, Prince of Wales, Somerset, Southampton, Coats (Ellef RIngnes).
Ecology and habitat. Substrates: wet meadows (clayey), marshes (e.g.
with Carex aquatilis), along streams, river terraces (and edges, e.g. in
colluvial, fluvial deposits), lake shores, tundra (furrows, berms and margins of
polygons), slopes (often with other grasses and Salix and Dryas;
sometimes very well vegetated), seashores; imperfectly drained moist areas, or
dry, or moderately well drained areas; calcareous; rocks, gravel, sand, silt,
clay, till; peat (sometimes). Habitats: Most commonly occurring on recently
disturbed silt or clay deposits, such as thaw flow slides, eroding banks, fine
grained floodplains. In wet clay or silt, by river banks or lake shores, on damp
but loose calcareous gravel, in small marshy depressions among polygons, on
sand, and occasionally in dry tundra, or in the centres of otherwise bare
mud-boils. Deschampsia brevifolia also occurs around construction sites
and settlements.
In an experiment where 10 plants collected on Ellesmere
Island, at Eureka, were moved to a transplant garden in the grounds of Nunavut
Arctic College, Iqaluit, the plants struggled for a few years and then died out.
Plants of this species are common in disturbed areas around Nettilling Lake, and
often eaten by geese. Re-growth after such grazing may result in a mat of plants
1–2 cm high that have been interpreted as Puccinellia phryganodes.
Taxon as an environmental indicator. This taxon is indicative of a location that has been recently disturbed, either by the influence of humans or because of natural disturbances characteristic of flood plains, slumping slopes, or frost boils.
Notes. This taxon was considered part of a D. cespitosa
‘complex’ by Kawano (1963, 1966) who investigated the cytogeography
and evolution of members of the complex from many parts of the world including
the eastern Canadian Arctic. He reported on the hypothetical relationships of
members of the D. cespitosa complex with chromosome numbers ranging from
2n = 26, 28, 35, 38, 39, 41, 49, 52, and 56 and noted that Tateoka (1955)
and Bowden (1960b) had reported the existence of ‘B’ or supernumerary
chromosomes in D. cespitosa.
Porsild (1964), recognized a taxon spelt
as D. caespitosa with ‘caes’ but the spelling
‘ces’ was used in the original description. Porsild (1964)
recognized D. cespitosa (now considered an excluded taxon) and three
other taxa within the genus Deschampsia, i.e. D. alpina, D.
brevifolia, and D. pumila (see D. paramushirensis).
Aiken
et al. (1995) attempted to follow Porsild (1957) and recognize both D.
cespitosa subsp. cespitosa and D. cespitosa subsp.
brevifolia. Further field work has established that there is a single,
phenotypically plastic taxon in the eastern Canadian Arctic, similar to the type
recognized by Robert Brown from Melville Island as D. brevifolia. The
taxa D. cespitosa s.s. and D. glauca as understood in northern
Europe, do not occur in the eastern Canadian Arctic. (E. Reidar, personal
communication 1999).
The phenotypic plasticity in this taxon was observed in
plants transplanted from Eureka Sound, Ellesmere Island (80°09'N,
86°00'W) in 1990, to Iqaluit, Baffin Island (64°44'N, 68°28'W)
and Ottawa, Ontario (45°18'N, 75°50'W). Over a three year period the
plants grown in Iqaluit became smaller and more stunted. Many of the 10 plants
grown in Ottawa died, but the one illustrated in the image library became larger
and with more diffuse inflorescences as photographed in 1994. In the photograph,
the previous season’s inflorescence as seen in the straw has tightly
appressed branches, the 1994 inflorescences have spreading branches. The voucher
for the original collection is of a plant approximately 16 cm high, the voucher
for the photograph in the image library is a plant 32–33 cm high.
The
very short awn is sometimes absent or broken and often overlooked, resulting in
small specimens being misidentified as Poa species.
Illustrations. • Herbarium specimen. Canada. Nunavut, Baffin Island, Nettilling Lake, 1986, Aiken 86–149. (CAN). • "Cultivated" plant. Plants brought from Ellesmere Island in 1991 and grown in Ottawa for three years. Note compact inflorescence of previous season's growth, and branching inflorescence in 1994's growth. • "Cultivated" plant close-up of inflorescence. Plants brought from Ellesmere Island in 1991 and grown in Ottawa for three years. Photographed in 1994. • Type specimen. N.W.T., Melville Island, 1819–20, Sabine, Edwards, Ross et. al. Duplicate type, mistakenly marked Dupontia. Collected on Capt. W.E. Parry's First Voyage and described by Robert Brown (BM). • 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).
