Flora of the Canadian Arctic Archipelago

DELTA
Home

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

Artemisia hyperborea Rydberg

Asteraceae (Compositae), Daisy family.

Published in N. Amer. Fl. 34 v, 3: 262. 1916.

Type: Nunavut; Bernard Harbour; sand dunes, F. Johansen, Field no. 304a, August 14, 1915. CAN!

Synonymy. Artemisia furcata auct.,

Vegetative morphology. Plants (5–)10–20 cm high; perennial herbs; caespitose. Only fibrous roots present (fibrous roots off underground stems usually), or taproot present (a main vertical root from a vertical caudex). Ground level or underground stems horizontal, or vertical; rhizomatous; elongate; 3–6 mm wide. Caudex present (much branched near ground level). Aerial stems developed; erect, or ascending. Aerial stem trichomes appressed. Leaves heterophyllous; mainly basal (pinnately dissected), or distributed along the stems (linear leaves); erect; alternate; dying annually and non-persistent. Petioles present; 5–30(–35) mm long; winged (at the base), or not winged (towards the apex); hairy; tomentose (felt-like). Petiole hairs shorter than the diameter of the petiole; appressed; straight, or curved; smooth. Leaf blades simple, or compound. Leaf blade bases obtuse, or cuneate. Blades 10–20 mm long, 1–12 mm wide, spreading, linear (flowering stems; basal leaves pinnately, or bipinnately divided, flabellate, i.e., with several leaf divisions terminating at the same level, blade divisions conspicuously more and narrower than in any of the other Arctic Artemisia species), flat, with inconspicuous veins. Blade adaxial surface hairy, hairs villous, tomentose, and short-silky ("silvery canescent", and occassionally long silky hairs on the margins), hairs simple, hairs dense, hairs white, or translucent (so dense the surface looks grey). Blade abaxial surface hairy, hairs tomentose and short-silky, hairs very dense, hairs white, hairs straight and curved, hairs appressed. Blades lobed or cut into linear divisions (basal leaves) or not lobed (flowering stem leaves). Blade margins entire, with non-glandular hairs; degree of incision 80–95% (3–5 primary divisions; 1–2 secondary divisions, and occasionally tertiary divisions); apices acute, or obtuse.

Reproductive morphology. Flowering stems with leaves. Flowering stems hairy. Flowering stems tomentose. Flowering stem hairs simple; shorter than the diameter of the flowering stem; white or translucent. Inflorescences of several flowering heads; terminal, or lateral (flowering stems have linear leaves and 1–3 heads borne on short pedicels or branches from the axils of the leaves); 2–10 cm long (Arctic islands, to 15 cm in specimens from continental North America). Flowering heads 3–6 mm deep; 4–8 mm wide; with only disc florets. Pedicels absent, or subtending flowering heads (if so, very short 1–3 mm long, rarely to 12 mm long (CAN 279012); with non-glandular hairs. Involucral bracts present. Number of rows 2–3. Outer involucral bracts mostly green (in the centre with a conspicuous brown, ovate, submarginal zone before a membranous margin that is wider towards the base); lying adjacent to the flowers; ovate (spatulate); 3.3–3.7 mm high; (1.5–)2–2.5 mm wide; densely hairy; without glandular hairs. Inner involucral bracts ovate; 3.3–3.7 mm high; 2–2.5 mm wide; margins wide, scarious for at least one quarter of the bract (broader towards the base); apex lacerate. Flowers radially symmetrical (actinomorphic). Sepals absent. Petals conventional; fused; 5; yellow; without contrasting markings; 3–3.2 mm long. Corolla tubular, or funnel-form; 5-lobed. Stamens 5. Anthers yellow; 1–1.2 mm long. Ovary inferior; carpels 2; syncarpous. Styles 1; 1.9–2.1 mm long. Stigmas per ovary 2. Placentation basal. Ovules per ovary 1. Fruit sessile; dry; cypselas; obovate; yellowish, or brown; 1.2–1.6 mm long; 0.5–0.6 mm wide; glabrous; surface venation ribbed; indehiscent. Seeds 1.

Chromosome information. 2n = no known counts.

Löve and Löve (1975) list five counts, two as arctic by Korobkov (1981), but these do not belong to this taxon.

Ecology and habitat. Substrates: tundra, slopes, ridges, barrens. Marine reworked carbonate, rich gravel, well-drained silt (CAN 489200, Victoria Island); marine reworked silty till (CAN 489199).

North American distribution. Alaska, Yukon, Northwest Territories Islands, continental Northwest Territories. Range in the Canadian Arctic Archipelago limited. Uncommon. Low Arctic. Arctic islands: Banks, Victoria.

Northern hemisphere distribution. North American (American Beringian). North Alaska – Yukon, Central Canada.

General notes. The type and other Canadian specimens have leaves covered with a "silvery canescence", that is, white, tomentose, and with short silky appressed hairs. The heads are almost always sessile or sub-sessile. In this they differ from the samples of A. furcata from Siberia at CAN, as on those samples the hairs are tawny, villous, long silky, and spreading from the surface of the plant. The Russian specimens usually have heads borne on conspicuous pedicels.

The eastern Canadian specimens also differ from those in Alaskan specimens of A. furcata, which is considered a reason to treat the taxa separately (Elven et al. 2003).

Illustrations. • Close-up of pressed plant. Note silvery grey leaves, the basal ones with with 3–5 primary divisions; 1–2 secondary divisions, those on the flowering stems simple. Outer involucral bracts mostly silvery green in the centre with a conspicuous brown, ovate, submarginal zone. Petals and anthers yellow. N.W.T., Victoria Island, Diamond Jenness Peninsula, 19 July, 1982. S.A. Edlund 445. CAN 489202. • Close-up of pressed inflorescence. Note outer involucral bracts mostly green in the centre with a conspicuous brown, ovate, submarginal zone that is wider towards the base. N.W.T., Victoria Island, Diamond Jenness Peninsula. 19 July, 1982. S.A. Edlund 445. CAN 489202. • Inflorescence of flowering heads. Inflorescence of numerous flowering heads (capitula) borne in the axils of linear leaves that are covered with tormentose and silky hairs that appear grey or silvery canescent. Pedicels absent. N.W.T., Banks Island. Aiken 99–040. CAN. • Close-up of inflorescence. Capitula in which the outer flowers have long strap-like stigmas exposed. More central flowers are at or approaching anthesis with the yellow strongly apiculate anthers visible and the petals spreading to expose the anthers. Note the long silky hairs on the leaves subtending the capitula. Aiken 99–040. 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.

.

Contents