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

Brassicaceae Burnett

English: Draba family.

Brassicaceae (Cruciferae), Draba family.

Vegetative morphology. Plants 1–150 cm high; biennial herbs, or perennial herbs; caespitose, or not caespitose; sometimes vegetatively proliferating in inflorescences, or never vegetatively proliferating by bulbils on stems or leaves, in inflorescences, from gemmiphores and gemmae, or by fragmentation. Taproot present, or only fibrous roots present. Ground level or underground stems horizontal, or vertical, or absent; rhizomatous, or stoloniferous; elongate, or compact; 0.5–1.5 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, or decumbent, or prostrate. Aerial stem trichomes appressed, or spreading, or erect. Leaves heterophyllous, or not heterophyllous; distributed along the stems, or mainly basal, or basal in a rosette; patent, or erect; alternate, or whorled; persistent, or dying annually and non-persistent, or marcescent. Petioles present, or absent; 0–30(–60) mm long; winged, or not winged; shallowly concave in cross section, or flat; glabrous, or hairy (very sparsely hairy on the margins); pubescent, or pilose. Petiole hairs shorter than the diameter of the petiole, or longer than the diameter of the petiole; spreading; straight. Leaf blades simple (usually), or compound. Leaf blade bases cordate, or truncate, or obtuse, or cuneate, or attenuate, or rounded, or hastate. Blades 1.5–40(–100) mm long, 0.3–10(–25) mm wide, appressed to the stem or spreading, flat, veins pinnate or veins reticulate or appearing single-veined or with inconspicuous veins. Blade adaxial surface dull (usually) or shiny, glabrous or glabrescent or scabrous or hairy, hairs puberulent or pilose or villous or woolly, hairs simple or branched or glandular or stellate, hairs sparse or moderately dense or dense, hairs white, or translucent or a mixture of white and yellow hairs. Blade abaxial surface glabrous or glabrescent or scabrous or hairy, hairs pubescent or pilose or villous or tomentose or woolly, hairs sparse or moderately dense or very dense, hairs white, hairs straight or curved or irregularly branched or stellate, hairs appressed or spreading or erect. Blades not lobed or cut into linear divisions. Blade margins entire or serrate or dentate or deeply divided, glabrous or with non-glandular hairs or with glandular hairs, with 0–3 teeth on each side of the blade, with teeth all around the blade or toward the base or toward the apex; degree of incision 80–90%. Hydathodes present and conspicuous, or present but inconspicuous, or absent. Blade apices acute, or obtuse, or rounded. Leaflet arrangement pinnate. Leaflets 3–17; 2–20 mm long; 0.5–4 mm wide; linear, or oblong, or obovate, or lanceolate, or oblanceolate; veins inconspicuous.

Reproductive morphology. Flowering stems shorter than the leaves, or about as high as the leaves, or conspicuously taller than the leaves; with leaves, or without leaves. Flowering stems hairy. Flowering stems puberulent, or pilose, or villous, or tomentose, or woolly. Flowering stem hairs simple, or branched, or stellate; shorter than the diameter of the flowering stem, or longer than the diameter of the flowering stem; white or translucent; glandular hairs present, or absent. Inflorescences racemose, or cymose, or fasciculate, or head-like; terminal, or lateral; dense, or diffuse; oblong, or lanceolate, or ovate, or globose or sub-globose; 0.5–2.5 cm long; 4–35 mm wide; elongating as the fruit matures, or not elongating as the fruit matures. Pedicels glabrous, or with non-glandular hairs. Flowers per inflorescence 2–70; small, or medium-sized, or large (rarely). Sepals conventional; 4; free; 0.5–2.2 mm long; 1.3–8.5 mm wide; green, or yellow, or brown, or purple, or pink, or purplish red; herbaceous, or scarious. Calyx glabrous, or hairy. Calyx hairs pilose, or villous, or woolly; non-glandular; white or translucent. Calyx margins ciliate, or margins without cilia. Petals conventional; free; same length as the calyx, or longer than the calyx; 4; green, or white, or yellow, or pink, or purple; ovate, or obovate, or oblanceolate, or spatulate, or obtriangular; unlobed, or slightly lobed or undulating; 1.8–15 mm long; 0.3–4(–6) mm wide. Stamens 6; stamen filaments markedly unequal in length. Anthers reddish, becoming yellow, or yellow; ellipsoid, or short-cylindrical, or ovoid, or sub-globose, or triangular; 0.1–2.5 mm long. Ovary superior; carpels 2; syncarpous. Ovaries pear-shaped, or ovate, or inverse turnip-shaped, or oblong, or sub-globose; glabrous, or hairy; pubescent, or pilose, or villous, or tomentose, or woolly. Ovary hairs moderately dense, or very dense; white; appressed, or spreading; straight, or wavy, or branched, or stellate. Styles present, or absent; 1; completely fused; thick and short; 0–2(–8) mm long; conical; basal portion smooth. Stigmas per ovary 1, or 2. Placentation parietal. Ovules per ovary 4–80. Fruit stalked; stalk 1–27 mm long; dry; a silique; spherical, or ellipsoid, or ovoid, or elongate-cylindrical, or oblong, or broadly lanceolate, or lanceolate; yellowish, or black, or brown, or purple, or blue, or green at maturity; 3–20(–100) mm long; 0.6–4(–9) mm wide; glabrous, or hairy, or glabrescent; surface venation reticulate, or appearing veinless, or venation ribbed; distinctly flattened, or not distinctly flattened; dehiscent; shedding the outer walls to expose a thin inner wall, with the seeds attached at the margins on either side. Styles remaining straight; persisting in fruit 0.05–2(–8) mm long. Seeds 4–80; 0.4–3 mm long; brown, or yellowish; surfaces smooth, verrucose, winged, rugose.

Illustrations. • Fruit. Family characterised by siliques; fruit that has a partition with seeds attached to the edges of the partition and not to the ovary wall.


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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