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

Asteraceae Dumortier

English: Daisy family.

Asteraceae (Compositae), Daisy family.

Vegetative morphology. Plants 2–30(–60) cm high; perennial herbs (usually), or annual herbs, or biennial herbs (rarely, i.e., Tephroseris palustris subsp. congesta and Tripleurospeumum maritimum), or perennial herbs; caespitose, or not caespitose; never vegetatively proliferating by bulbils on stems or leaves, in inflorescences, from gemmiphores and gemmae, or by fragmentation; with milky juice, or without milky juice. Taproot present, or only fibrous roots present. Ground level or underground stems horizontal, or vertical; rhizomatous, or stoloniferous; elongate, or compact; 0.5–10 mm wide. Caudex present, or absent. Aerial stems a small transition zone between taproot and basal leaves, or branching from a tap at or near ground level into two or more branches, or developed; erect, or ascending. Aerial stem trichomes appressed, or spreading, or erect. Leaves mainly basal and distributed along the stems, or basal in a rosette; patent, or erect; alternate, or opposite (Arnica); dying annually and non-persistent, or marcescent. Petioles present, or absent; 0–80(–100) mm long; winged, or not winged; flat; glabrous, or hairy, or glabrescent; pubescent, or pilose, or villous, or tomentose, or woolly, or long-silky. Petiole hairs shorter than the diameter of the petiole, or longer than the diameter of the petiole; appressed, or spreading, or erect; straight, or floccose, or curved, or wavy; smooth. Leaf blade bases truncate, or obtuse, or attenuate, or rounded. Blades 2–120 mm long, 1–30(–70) mm wide, spreading or divaricate, straight, linear or lanceolate or oblanceolate or obovate or spatulate, flat, veins pinnate or veins palmate or appearing single-veined or with inconspicuous veins. Blade adaxial surface with sessile glands (rarely) or without sessile glands, glabrous or glabrescent or hairy, hairs pubescent or pilose or villous or woolly or long-silky, hairs simple (and) or glandular, hairs sparse or moderately dense or dense (if applicable), hairs white, or translucent or grey or a mixture of white and yellow hairs or multicellular with deep purple pigment at the cell end walls or tawny. Blade abaxial surface glabrous or glabrescent or hairy, hairs puberulent or pilose or villous or tomentose or woolly or short-silky or long-silky, hairs sparse or moderately dense or very dense (often sparse near the base of the flowering stem and dense near the flowering head(s)), hairs white or rust-coloured or a mixture of white and yellow, hairs straight or curved or wavy, hairs appressed or spreading or erect. Blades lobed or not lobed or cut into linear divisions. Blade margins entire or glandular-dotted or serrulate or serrate or crenate or dentate or deeply divided or runcinate, glabrous or with non-glandular hairs or with glandular hairs; degree of incision 5–95%; apices acuminate, or acute, or obtuse, or rounded. Leaflets veins inconspicuous. Apical leaflet base not distinctly stipitate (if applicable).

Reproductive morphology. Plants dioecious, or bisexual, or agamospermic. Flowering stems with leaves, or without leaves. Flowering stems hairy. Flowering stems pilose, or villous, or tomentose, or woolly. Flowering stem hairs simple; shorter than the diameter of the flowering stem, or longer than the diameter of the flowering stem; white or translucent, or brown, or transparent with deep purple cross-walls; glandular hairs present, or absent. Inflorescences solitary heads, or of several flowering heads; terminal, or lateral; ovate, or globose or sub-globose, or obovate, or ellipsoid; 0.7–15(–20) cm long; 10–160 mm wide. Flowering heads 3–15(–30) mm deep; 2.5–60 mm wide; with only disc florets, or with only ligulate florets, or with disc and ray florets. Pedicels absent, or subtending flowering heads; glabrous, or with non-glandular hairs. Involucral bracts present. Number of rows 1–3(–5). Outer involucral bracts mostly green, or mostly wine red or purple pigmented, or outermost bracts green, sometimes with red pigment in centre; innermost bracts frequently purple or occasionally green, or outermost bracts green, with brown or red edges; innermost bracts almost transparent with red or brown central area, or with a green central portion and wide dark margins, or with silvery grey central area and wide brown margins; strongly reflexed, or lying adjacent to the flowers, or spreading to erect; linear, or oblong, or lanceolate, or ovate; 1.5–10(–15) mm high; 0.5–3 mm wide; glabrous, or sparsely hairy, or densely hairy; with glandular hairs, or without glandular hairs. Inner involucral bracts oblong, or lanceolate, or ovate, or obovate; 2.5–20 mm high; 0.4–3.5 mm wide; margins wide, scarious for at least one quarter of the bract, or narrow and scarious, less than one quarter of the bract; apex prominently horned, or sometimes callused, but without a prominent horn, or with or without horns or calluses, or entire, or lacerate. Flowers radially symmetrical (actinomorphic), or bilaterally symmetrical (zygomorphic); unisexual, or bisexual (or a mixture of both). Sepals conventional, or absent, or represented by a pappus; accrescent, or non-accrescent. Pappus with a single row of hairs, or with a double row of hairs; yellowish (rarely), or whitish. Ray florets pappus 2.8–12(–15) mm long. Disc florets pappus 3.3–8(–12) mm long. Petals conventional; fused; longer than the calyx (usually); 5; white, or yellow, or red, or pink, or purple, or brown; with contrasting markings, or without contrasting markings; 1–11(–13) mm long; not spurred. Corolla tubular, or funnel-form, or flat, strap-like; unlobed, or 3-lobed, or 5-lobed (lobes sometimes poorly defined in ray florets). Ray florets 3–130; limb 4–20(–30) mm long; limb 0.5–2(–4) mm wide. Stamens present, or absent; 5 (usually); free of the corolla (the anthers are connivent into a tube, but not attached to the corolla). Anthers yellow (usually), or purple (Saussurea); long-cylindrical (if applicable); 0.9–2.6 mm long. Ovary inferior; carpels 2; syncarpous. Styles 1; completely fused (the terminal portion of the style dividing into two long or short stigmatic branches); 1.5–12(–16) mm long. Stigmas per ovary 2. Placentation basal. Ovules per ovary 1. Fruit sessile; dry; cypselas; elongate-cylindrical, or obovate, or oblong, or clavate, or urceolate; yellowish, or black, or brown, or red, or straw-coloured; 1–5.5 mm long; 0.3–1.2 mm wide; surface appearing veinless, or venation ribbed; indehiscent. Seeds 1.

Illustrations. • ray and disc florets. Capitulum composed of white ray florets and yellow disc florets. Ray florets may have three teeth (red arrows) on the ends of their strap-like petals. • ligulate flowers only. Close-up of capitulum inflorescence composed only of ligulate flowers. The ends of the strap-like petals have five teeth. • disc florets only. Flowering head, capitulum composed only of white disc florets that have stigmas exposed.


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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