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 pratensis L. subsp. colpodea (Th.Fries) Tzvelev

Poaceae, Grass family.

Published in Novosti Sist. Vyssh. Rast. 9: 47. 1972.

Type: Norway: Svalbard, Spitsbergen, Liefdebay, leg. Th.Fries. Holotype: S?

Synonymy. Poa stricta Lindeb. subsp. colpodea Th.Fr., Öfvers. Förh. Kongl. Svenska Vetensk.-Akad. 1869, 26: 138. 1870.

Poa alpigena Lindm. var. colpodea (Th.Fr.) Schol., Skr. Svalbard Nordishavet 62: 89. 1934.

Poa rigens Hartm. subsp. colpodea (Th.Fr.) D. Löve, Taxon 17: 89. 1968.

Poa pratensis L. subsp. colpodea (Th.Fr.) Tzvelev, Novosti Sist. Vyssh. Rast. 9: 47. 1972.

Poa alpigena Lindm. subsp. colpodea (Th.Fr.) Jurtz. and V.V. Petrovsky, Byull. Moskovsk. Obshch. Isp. Prir., Otd. Biol. 85, 6: 100. 1980.

Poa pratensis L. subsp. alpigena (Lindm.) Hiitonen var. colpodea (Th.Fr.) Soreng, Phytologia 71: 403–404. 1991[1992].

Poa pratensis L. f. prolifera Simmons, Vasc. Pl. in the Fl of Ellesmereland, 169. 1906.

Vegetative morphology. Plants (10–)20–60(–65) cm high (leafy for more than three quarters of the plant height); perennial herbs; not caespitose (but with stems in loose clusters); sometimes vegetatively proliferating in inflorescences. Only fibrous roots present. Ground level or underground stems horizontal; rhizomatous (forming turf in suitable habitats in the Low Arctic, often only a single culm per season in harsh environments. Shoots mainly arising extravaginally); elongate, or compact. Aerial stems erect. Leaves present; mainly basal, or distributed along the stems; alternate; marcescent. Prophylls 5 mm long (in extravaginal branches). Petioles absent. Sheaths present; with the margins fused only in the lower part (1/4–1/2); glabrous, or with trichomes; scabrous (minutely so, when present); sheath collars present. Ligules present; 0.9–3.1 mm long (lower leaves 0.9–2.2 mm; upper leaves 2.0–3.0 mm); membranous; glabrous, or hairy (abaxially puberulent); ovate-oblong. Ligule apices obtuse; entire. Leaves grass-like. Blades 30–170 mm long, 0.4–1.8 mm wide (when folded), appressed to the stem or spreading, folded in bud, linear, flat (usually) or folded, veins parallel, midvein similar in size to other veins in the leaf, bulliform cells in distinct rows on either side of the midvein. Blade adaxial surface glabrous or scabrous. Blade abaxial surface glabrous (usually).

Reproductive morphology. Flowering stems circular or oval in cross section. Flowering stems with leaves; culm nodes not exposed (in short plants), or becoming exposed; culm nodes number visible 0–2. Inflorescences paniculate; dense, or diffuse (at anthesis); lanceolate, or pyramidal; 3–12.5 cm long; 10–70 mm wide (pancile narrow, about three times as long as wide). Inflorescences main axis glabrous. Number of inflorescence branches at lowest node (1–)2–5. Inflorescence primary branches 17–50 mm long; glabrous (or nearly so, with spikelets evenly distributed along the branches); with spreading secondary branches. Spikelets disarticulating above the glumes; ovate; 4–5.2 mm long; 1.4–2.5 mm wide (sometimes vegetatively proliferating). Florets per spikelet 2–3. Two glumes present (distinctly keeled, the keels scabrous above.). First glume 0.7–0.85 × the length of the second glume; 0.45–0.55 × spikelet length; 1.9–2.8 mm long; ovate; glabrous, or with trichomes (with 3–4 minute prickles on the midvein); margins glabrous; veins 1; apex acute (a contrast with Poa arctica R. Br.). Second glume 0.4–0.9 × as long as the spikelet; almost as long as, or longer than, the lowest floret (or barely as long); 2.6–3.3 mm long. Second glume ovate. Second glume glabrous, or with trichomes (scaberulous); veins 3. Rachilla not pronounced between the florets; extending beyond the uppermost floret; internode 1.3–1.8 mm long (approximately); internode glabrous. Callus differentiated (as a thick web, slightly separated from the tuft of hairs at the lanate base of the lemma); hairs curly; hairs shorter than the floret. Lemma lanceolate (broadly); 3–4 mm long; keeled (slightly, the base sparsely lanate, the margins and keel with long hairs, but elsewhere almost glabrous); surface dull (margins thinner than the body of the lemma); surface hairy; surface with trichomes on veins only (mainly on marginal veins and keel, and often on the intermediate veins); veins 5; apex rounded; apex entire; awnless. Palea well developed; 2.7–3.4 mm long; veins scabrous to hairy. Flowers bilaterally symmetrical (zygomorphic). Perianth represented by lodicules. Stamens 3. Anthers 1.4–1.8 mm long. Ovary superior; carpels 3; syncarpous. Styles 2. Placentation basal. Ovules per ovary 1. Fruit sessile; dry; a caryopsis; 1.8–2.4 mm long; indehiscent. Seeds 1.

Chromosome information. 2n = 35, 43, 56, 70, 71, 72, and 84 (Flora Europaea, 1980. Löve and Löve (1975) found chromosome numbers between 2n = 28 and 127 occurred, although the most frequent numbers were 56–84. Euploid numbers were more frequent than aneuploid. No differences in vitality between plants with euploid and aneuploid numbers were observable.).

2n (8x) = 56. Flovik (1938, 1940, Svalbard); Nannfeldt (1940); Nygren (1950a, 1950b, 1954a); Holmen (1952, Greenland); Löve (1981b, northern Canada, as P. tolmatchewii). The report of Jørgensen et al. (1958 Greenland) probably also belongs here.

Ploidy levels recorded 8x.

Ecology and habitat. Substrates: wet meadows, snow patches, around the margins of ponds, along streams, river terraces, tundra (sometimes in rich meadows), slopes, ridges, cliffs (exposed); imperfectly drained moist areas, dry, moderately well-drained areas; rocks, gravel, sand, silt, clay, moss; with high organic content (occasionally); acidic, or calcareous, or nitrophilous ((e.g., owl perches). Elven (personal communication, 2005) noted that this species occurs on damp sand and gravel, often in swales (away from the sea) and depressions and along brooks and small lakes. Almost always in fairly open vegetation. It seems to be indifferent (both acidic and basic substrates).

North American distribution. Alaska (?), Yukon (?), Northwest Territories Islands, continental Northwest Territories (?), Nunavut Islands, continental Nunavut (?). The material we have confirmed is from northernmost Canada, Greenland, Svalbard, Franz Joseph Land, and northern Siberia. No signs of the 'colpodea' entity were found in Alaskan material (ALA) (Elven, personal communication, 2005).

Northern hemisphere distribution. Circumpolar (with gaps). Kanin–Pechora, Svalbard – Franz Joseph Land, Polar Ural – Novaya Zemlya, Yamal–Gydan, Taimyr – Severnaya Zemlya, Anabar–Olenyok, Kharaulakh, Yana–Kolyma, West Chukotka, Wrangel Island, East Chukotka (?), North Alaska – Yukon (?), Central Canada, Labrador – Hudson Bay, Ellesmere Land – Peary Land, West Greenland, East Greenland.

General notes. Haugen (2000) tested two of Tzvelev's hypotheses about the hybrid origins of taxa in Poa using material collected in Svalbard. The entities investigated and compared in her thesis were P. abbreviata, P. alpigena viviparous type, P. alpigena subsp. colpodea, P. arctica subsp. arctica, P. arctica subsp. cespitans, P. glauca, and P. hartzii. The investigation concerned morphology (about 50 characters), biological reproductive characteristics, and isoenzymes as genetical markers. The samples of Poa alpigena and P. arctica investigated were insufficiently separated in most morphological characters (except the lemma hairiness) and also less distinct in isoenzymes than would be expected of two 'species' from different aggregates. Poa alpigena subsp. colpodea was fairly distinct, both morphologically and enzymatically. In morphology, it was a little more distant from 'normal' P. alpigena than the latter was from P. arctica subsp. arctica. In enzymes, however, P. alpigena subsp. colpodea was closer to P. alpigena s.s. than to P. arctica. Poa alpigena subsp. colpodea was described from Svalbard, and the plants Hagen (2000) investigated corresponded to the type and to plants named as such from arctic North America. What these results imply is that it is difficult to separate between the aggregates around Poa arctica and P. pratensis, the latter exemplified by Svalbard P. alpigena var. vivipara and subsp. colpodea.

Elven (personal communication, 2005) noted that Soreng et al. (2003) accepted subsp. colpodea but circumscribed it widely and included, e.g., "P. alpigena var. vivipara". Here we consider viviparous P. pratensis supbsp. alpigena as distinct from P. pratensis subsp. colpodea.

Illustrations. • Close-up of plant. Rhizomatous plants with green culms that are purplish at base. Mostly purplish inflorescence with vegetatively proliferating spikelets. Sparse in moist sand on lower slope of a 2–3 m high bank (3 small populations seen in area). Nunavut, Ellesmere Island, Tanquary Camp, 8124'N, 7652'W. 22 July, 1999. L.J. Gillespie 6482 and L.L. Consaul. 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.