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

Pleuropogon sabinei R. Br.

English: Semaphore grass,

French: Pleuropogon de Sabine,

Inuktitut: Iviit, ivisuka, ivitsuskaka.

Poaceae, Grass family.

Published in Chlor. Melvill. 31. 1823.

Type: Canada: Melville Island, leg. Parry (BM, plant in lower right-hand corner) lectotype, selected by But, Novon 4: 16. 1994. Isotype: GH!.

Synonymy. Pleuropogon sabinii f. aquaticus Simmons, Rep. 2nd Norwegian Arct. Exp. Fram 2: 170. 1906. Type: Canada. Nunavut: Ellesmere Island, Fram Fjord ("in lacubus, rivulis, etc."), 26 Aug. 1899, H.G. Simmons 1600. Holotype: O! Isotype: CAN!.

P. sabinii f. terrestris Simmons. Rep. 2nd Norwegian Arct. Exp. Fram 2: 170. 1906. Type: Canada. Nunavut: "Ellesmerelandiae; in sinu Fram Fjord," 26 Aug. 1899. H.G. Simmons 1666. Holotype O. Isotype GH!.

Vegetative morphology. Plants 4–30 cm high (emergent); perennial herbs; not caespitose. Only fibrous roots present. Ground level or underground stems horizontal; rhizomatous; elongate, or compact; 1–2 mm wide. Ground level or underground stems scales present; surfaces smooth; 10–40 mm long; glabrous. Aerial stems erect, or decumbent. Leaves present; distributed along the stems (submerged leaves lax and floating, emergent leaves erect); alternate; marcescent. Petioles absent. Sheaths present; with the margins fused to the apex; glabrous; sheath collars present. Ligules present; 0.9–2.7(–3.5) mm long; membranous, or a fringed membrane (on the isotype specimen); glabrous, or hairy; ovate-oblong. Ligule apices obtuse; entire. Leaves grass-like. Blades 20–230 mm long, 1.5–3 mm wide (when flat), appressed to the stem or spreading, folded in bud, linear, flat or folded, veins parallel, midvein conspicuously larger than the lateral veins (sometimes with an associated thickened ridge of tissue below the abaxial surface), bulliform cells in distinct rows on either side of the midvein. Blade adaxial surface glabrous. Blade abaxial surface glabrous.

Reproductive morphology. Flowering stems circular or oval in cross section. Flowering stems with leaves; rooting at the lower nodes; culm nodes not exposed (when culms emerge), or becoming exposed (when culms remain submerged); culm nodes number visible 0–3. Inflorescences racemose (with long spikelets arranged as though signalling semaphore); diffuse; linear; 3–6.5(–8) cm long; 2–7 mm wide. Inflorescences main axis glabrous. Number of inflorescence branches at lowest node 1. Spikelets disarticulating above the glumes; oblong; 8–18 mm long; 1.7–5 mm wide. Florets per spikelet 6–10. Two glumes present. First glume 0.4–0.9 × the length of the second glume; 0.1–0.2 × spikelet length; 1.3–1.6 mm long; lanceolate, or ovate; glabrous; margins glabrous; veins 1 (faint); apex obtuse. Second glume 0.4 × as long as the spikelet or less; shorter than the lowest floret; 1.5–3(–4.3) mm long. Second glume ovate. Second glume glabrous; veins 3. Rachilla not pronounced between the florets; extending beyond the uppermost floret; internode 0.8–1.3 mm long; internode glabrous. Lemma oblanceolate; 3.5–4.7 mm long; rounded on the back; surface dull; surface sparsely scabrous; surface with trichomes on and between the veins; veins (6–)7; apex rounded, or truncate; apex entire, or erose, or lacerate; apex glabrous; awnless. Palea well developed; 3.4–4.5 mm long; veins scabrous (a dark purple, scabrous, awn 1.5–2 mm long arises near the base of each palea keel and often protrudes from the edges of the spikelet). Flowers bilaterally symmetrical (zygomorphic). Perianth represented by lodicules. Stamens 3. Anthers 1.6–2.6 mm long. Ovary superior; carpels 3; syncarpous. Ovaries glabrous. Styles 2. Placentation basal. Ovules per ovary 1. Fruit sessile; dry; a caryopsis; 2–2.2 mm long; indehiscent. Seeds 1.

Chromosome information. 2n = 40. Holmen (1952, Greenland); Jørgensen et al. (1958, Greenland); Löve and Ritchie (1966, northern Canada); Hedberg (1967, northern Canada); Zhukova (1969, northeastern Asia); Zhukova and Petrovsky (1976, western Chukotka); Löve (1978a);

2n = 42. Bowden (1960a); Mosquin and Hayley (1966, northern Canada); Zhukova et al. (1973, Russia); Zhukova and Tikhonova (1973, Chukotka); Yurtsev and Zhukova (1978, eastern Chukotka); Krogulevich (1984, Siberia).

Taxon as an environmental indicator. Indicative of low-lying areas where water accumulates for much of the growing season and the substrate remains damp all season.

Ecology and habitat. Substrates: wet meadows, around the margins of ponds (emergent or at the edges), marshes, along streams, lakeshores, tundra; aquatic, imperfectly drained moist areas; silt, moss; acidic (granite, gneiss, CAN 514341), or calcareous. Plants grow in the shallow waters of ponds, lakes, or sluggish streams, or on poorly drained soils around ephemeral ponds and terrain that is flooded earlier in the summer. On soft muddy shores of small sheltered ponds, plants of this species may form pure stands. Pleuropogon sabinei has been found in the small pond used as a water reservoir by Parks Canada at Tanquary Fiord, Ellesmere Island, 81°N, 79°45'W, and is common in the ponds to the west of the Polar continental Shelf Base, at Resolute, Cornwallis Island, 71°41'N, 94°54'W.

North American distribution. Alaska, Northwest Territories Islands, Nunavut Islands, continental Nunavut, northern Quebec, Labrador (?). Range in the Canadian Arctic Archipelago widespread. Common. High Arctic. Arctic islands: Baffin, Devon, Ellesmere, Axel Heiberg, Parry islands (Bathurst, Melville, Prince Patrick), Cornwallis, Banks, Victoria, Prince of Wales, Somerset, King William, Southampton, Coats (Ellef Ringnes and Prince Charles Islands and Boothia Peninsula).

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

General notes. This species has the most northern distribution for an emergent grass. Data for Canadian samples suggests some specimens are larger plants than those that occur in northern Europe. The taxon was named for the Arctic explorer Edward Sabine. The spelling of "sabinii" appears to have been a deliberate Latinising of the name by Robert Brown, and according to the International Code of Botanical Nomenclature, Articles 60,1 and 60,11, the spelling should be corrected (Greuter et al. 1994).

Illustrations. • Habitat: Cape Dorset. Plants of signal grass near scale bar marker, on the edge of a ditch. Nunavut, Baffin Island, Cape Dorset. 3 August, 2005. Aiken 05–085. CAN. Scale bar in cm. • Close-up of plants. Purple inflorescences of signal grass growing near the marker on the edge of a ditch. Nunavut, Baffin Island, Cape Dorset. 3 August, 2005. Aiken 05–085. CAN. • Habitat: Resolute Bay. Plants growing in shallow pond on calcareous silt. Note aquatic leaves that tend to float on the surface of the water. Nunavut, Cornwallis Island, Resolute Bay. Aiken 98–057. Photograph by Mollie MacCormac. • Habitat: Resolute Bay. Plants growing in shallow pond on calcareous silt. Note "semaphore" positions of the spikelets on the aerial culms and the floating aquatic leaves. Nunavut, Cornwallis Island, Resolute Bay. Aiken 98–057. Photograph by Mollie MacCormac. • Close-up of plant. Aerial culms with developing inflorescences having many flowered spikelets. Plants growing in shallow pond on calcareous silt. Nunavut, Cornwallis Island, Resolute Bay. Aiken 98–057. Photograph by Mollie MacCormac. • Close-up of plant: Baffin Island. Inflorescence of 5 to 6 spikelets oriented in different directions. Nunavut, Baffin Island, Cape Dorset. August, 2005. Aiken. No voucher. Scale bar in cm. • Close-up of two spikelets. Spikelet 10–15 mm long with two white stigmas per floret exposed. Nunavut, Baffin Island, Cape Dorset. August, 2005. Aiken. • Spikelets showing awns on paleas. Lemmas awnless, paleas with awns 1.5–2 mm long that arise near the base of each palea keel and protrude from the edges of the spikelet. Nunavut, Baffin Island, Cape Dorset. August, 2005. Aiken. • Possible isotype specimen. Canada, Melville Island. 1819–20. Sabine, Edwards, Ross et al. (Possible Isotype: GH). • Isotype, forma terrestris. Pleuropogon sabinei f. terrestris. Nunavut, Ellesmere Island, Fram Fjord. 1899. Herman G. Simmons 1666. (Isotype: GH). • Isotype, forma aquaticus. Pleuropogon sabinei f. aquaticus. Nunavut, Ellesmere Island, Fram Fjord. 1899. Herman G. Simmons 1600. (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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