Flora of the Canadian Arctic Archipelago
| Flora of the Canadian Arctic Archipelago | |
Brassicaceae (Cruciferae), Draba family.
Published in Syst. Nat. 2: 342. 1821.
Type: Alaska: "Insula Sti Pauli" [St. Paul I.], leg. Langsdorff. Holotype: probably G-DC.
Synonymy. Draba luteola auct., non Greene (1899).
Vegetative morphology. Plants 10–20(–40) cm high; perennial herbs (short-lived); not caespitose, or caespitose (loosely). Taproot present. Ground level or underground stems horizontal (giving rise to tufts of new plants); rhizomatous (between rosettes), or stoloniferous; elongate, or compact; 1–1.5 mm wide. Caudex present. Aerial stems erect (stiffly). Aerial stem trichomes spreading. Leaves mainly basal and distributed along the stems; alternate; dying annually and non-persistent, or marcescent (with small build-up). Petioles absent (but long attenuated leaf bases sometimes present). Leaf blades simple. Leaf blade bases truncate, or attenuate. Leaves not grass-like. Blades (10–)15–25(–30) mm long, 2–4(–5.5) mm wide, appressed to the stem or spreading, ovate or oblanceolate or obovate, appearing single-veined. Blade adaxial surface hairy, hairs branched or stellate, hairs sparse, hairs white, or translucent. Blade abaxial surface hairy, hairs sparse or moderately dense, hairs white, hairs irregularly branched, hairs spreading. Blade margins entire or dentate (sparsely in the upper third), with non-glandular hairs (similar to those on the leaf surfaces); apices acute.
Reproductive morphology. Flowering stems with leaves. Flowering stem hairs simple (relatively long), or branched (irregularly); shorter than the diameter of the flowering stem; white or translucent. Flowers in inflorescences. Inflorescences head-like; dense (in flower); globose or sub-globose; elongating as the fruit matures. Pedicels glabrous, or with non-glandular hairs (sparse). Flowers per inflorescence (3–)5–15; small. Sepals conventional; 4; free; 0.8–1.1 mm long; 2.2–2.8 mm wide; green, or purple (tinged). Calyx hairy (with a few simple hairs). Calyx hairs pilose; non-glandular; white or translucent. Petals conventional; free; 4; white; obovate; unlobed; 3.5–4.5 mm long; 1–1.5 mm wide. Stamens 6; stamen filaments markedly unequal in length; stamen filaments glabrous. Anthers yellow; sub-globose; 0.4–0.6 mm long. Ovary superior; carpels 2; syncarpous. Ovaries inverse turnip-shaped (oblanceolate); glabrous (glabrescent), or hairy (with a few sparse hairs). Ovary hairs white (if applicable); spreading; straight. Styles 1; thick and short; 0.4–0.8 mm long; straight. Stigmas per ovary 1. Placentation parietal. Ovules per ovary 20–24. Fruit stalked; stalk 2–8 mm long; dry; a silique; elongate-cylindrical, or lanceolate; green at maturity, or purple (tinged); 8–10(–12) mm long; 2–2.2 mm wide; hairy (with sparse short, simple or slightly forked hairs); surface appearing veinless; distinctly flattened; dehiscent; shedding the outer walls to expose a thin inner wall, with the seeds attached at the margins on either side. Styles persisting in fruit 0.4–0.8 mm long. Seeds 20–24; 0.9–1.1 mm long; brown, or yellowish; surfaces smooth.
Chromosome information. 2n = 64, or 80.
2n (8x) = 64. Zhukova and Petrovsky (1984, northeastern Asia);
2n (10x) = 80. Heilborn (1927); Mulligan (1970, Yukon);
2n = 82. Mulligan (2003, 2 counts).
Löve and Löve (1975) reported only the decaploid number (2n = 80) for this species. They reported the species as Beringian only, but at least three of the six counts they listed are from Greenland or Svalbard (Flovik 1940, Jørgensen et al. 1958, Böcher 1966a) where this species is not recognised.
Ploidy levels recorded 8x/10x.
Ecology and habitat. Substrates: tundra, flood plains; gravel, till. Sheltered turfy area (CAN 561469); gravel beach beside lake (CAN 561159).
North American distribution. Arctic islands: Banks, Victoria.
General notes. G.A. Mulligan annotated plants from Ferguson Lake on Victoria Island, 69°25'N and 105°15'W (CAN 561159, CAN 561455), as belonging to this taxon in 1968, and this record is mapped in Porsild and Cody (1980). A second record from Banks Island, Masik River, 71°37'N, 123°06'W (CAN 561469), was annotated by Mulligan the same year but not mapped in Porsild and Cody (1980).
Illustrations. • Close-up of plant. Plant with well-developed taproot, loosely branching caudex, and stiffly erect leafy stems. Nunavut, Victoria Island. DAO 561455. • Close-up of base of plant. Leaves in a basal tuft from a sprawling horizontal stem, petioles absent. right-hand leaf has a long attenuated leaf base. Leaf blade bases truncate; blades attenuate, oblanceolate, or obovate; appearing single-veined, margins entire or sparsely dentate in the upper third. Nunavut, Victoria Island. CAN 561455. • Close-up of inflorescence in late flowering stage. Inflorescence subglobose, flowering stems more densely hairy near the inflorescence, flowers with calyx green, or purple (tinged); with a few simple hairs, petals white, obovate, unlobed. Nunavut, Victoria Island. CAN 561455. • Close-up of elongating fruiting inflorescence. Fruit lanceolate, green with a purplish tinge. Mason 113. 22 July, 1968. DAO 561469. • 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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