Flora of the Canadian Arctic Archipelago
Brassicaceae (Cruciferae), Draba family.
Published in In Jacq., Misc. Austriac. 1: 147. 1778.
Type: Described from Austria: "e monte Flatnitz Carinthiae", leg. Jacquin. Isotype: G-DC.
Synonymy. Draba fladnizensis Adams f. glabrata (Lindb.) Polunin, J. Bot. 76: 99. 1938.
Vegetative morphology. Plants 4–10 cm high; perennial herbs; caespitose. Taproot present. Caudex present (branched or unbranched). Aerial stems erect. Aerial stem trichomes spreading. Leaves mainly basal (rarely with only 1–2 small leaves); alternate; dying annually and non-persistent. Petioles absent. Leaf blades simple. Leaf blade bases attenuate. Leaves not grass-like. Blades 5–9 mm long, 2–2.5 mm wide, ovate or obovate, appearing single-veined. Blade adaxial surface glabrous or scabrous, hairs simple and branched, hairs sparse (a few scattered hairs), hairs white, or translucent. Blade abaxial surface glabrous or hairy, hairs sparse, hairs white, hairs irregularly branched, hairs spreading. Blade margins entire, with non-glandular hairs or glabrous; apices acute.
Reproductive morphology. Flowering stems two or more per plant; without leaves. Inflorescences racemose; elongating as the fruit matures (especially in good growing conditions). Pedicels glabrous. Flowers per inflorescence 3–6; small; radially symmetrical (actinomorphic). Sepals conventional; 4; free; 1.2–1.7 mm long; 2–2.5(–3) mm wide; green and purple; herbaceous. Calyx glabrous, or hairy. Calyx hairs non-glandular; white or translucent. Petals conventional; free; 4; white; without contrasting markings; obovate; slightly lobed or undulating; 3.5–4 mm long; 1.5–2(–2.5) mm wide. Stamens 6; stamen filaments markedly unequal in length; stamen filaments glabrous. Anthers yellow; 0.5 mm long. Ovary superior; carpels 2; syncarpous. Ovaries ovate; glabrous. Styles 1; 0.1 mm long; straight. Stigmas per ovary 1. Placentation parietal. Ovules per ovary (16–)20–24(–28). Fruit stalked; stalk 4–6 mm long; dry; a silique; ovoid; purple; 7–9 mm long; 2–3 mm wide; glabrous, or hairy (rarely sparsely pubescent with unbranched trichomes); 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 0.2 mm long (or nearly obsolete). Seeds (16–)20–24(–28); 0.7–0.9 mm long; brown; surfaces verrucose.
Chromosome information. 2n = 16.
2n (2x) = 16. Heilborn (1927, Norway); Löve and Löve (1956, Iceland); Jørgensen et al. (1958, Greenland); Merxmüller and Buttler (1964, central Europe); Böcher (1966a, Greenland and Svalbard); Knaben (1966, Norway); Knaben and Engelskjøn (1967, Norway); Buttler (1967, central and southern and northern Europe); Zhukova and Tikhonova (1971, 1973, eastern Chukotka); Mulligan (1974b, northwestern Canada, Yukon, two counts); Engelskjøn (1979, Svalbard); Zhukova and Petrovsky (1980, western Chukotka: 1984, 1987b, northeastern Asia); Löve and Löve (1982, Arctic Canada); Brochmann et al. (1993, Svalbard); Grundt et al. (2004a and 2004b, Alaska, Canada, Greenland, Svalbard, Norway, Siberia, diploid in cytometry).
Ploidy levels recorded 2x.
Ecology and habitat. Substrates: hummocks; dry; gravel; with low organic content; calcareous, or circum-neutral.
North American distribution. Alaska, Yukon, continental Northwest Territories, Nunavut Islands, continental Nunavut, northern Quebec (?), Labrador. Range in the Canadian Arctic Archipelago widespread. Common. Arctic. Arctic islands: Baffin, Devon, Ellesmere, Parry islands.
Northern hemisphere distribution. Circumpolar, or circumboreal (arctic-alpine). Northern Fennoscandian, KaninPechora, Svalbard Franz Joseph Land, Polar Ural Novaya Zemlya, YamalGydan, Taimyr Severnaya Zemlya, AnabarOlenyok, Kharaulakh, West Chukotka, Wrangel Island, South Chukotka (?), East Chukotka, West Alaska, North Alaska Yukon, Central Canada, Labrador Hudson Bay, Ellesmere Land Peary Land, West Greenland, East Greenland.
General notes. In its entire geographical range Draba fladnizensis is known to be diploid, 2n = 16.
The confusion between D. fladnizensis and D. lactea has been due to doubts about the latter species and name (see D. lactea for discussion of its type). The two species are distinct, both morphologically and genetically, and D. lactea is not closely related to D. fladnizensis but rather to the amphi-Beringian D. palanderiana Kjellm. (Grundt et al. 2005).
Brochmann et al. (1993) found interpopulational F1 hybrids in D. fladnizensis to be entirely sterile, suggesting that this predominantly inbreeding diploid species comprises at least two sibling species, possibly isolated by genetic barriers. Crossing experiments within and between populations of D. fladnizensis (Grundt et al. 2005) in a circumpolar range have subsequently documented extensive within-species incompatibility, i.e., the occurrence of very numerous sibling species.
Draba subcapitata (in Pilosae) and D. fladnizensis (in Lacteae) are genetically and morphologically close (Scheen 1999, Scheen et al. 2002) and must belong to the same series if the series shall have any taxonomic value. Both species are much more different from D. lactea and from D. pilosa than from each other.
Scheen et al. (2002) studied the delimitation of D. lactea and D. fladnizensis morphologically, enzymatically, and using DNA (RAPD) to test the hypothesis that the origin of D. lactea (reported as a hexaploid) is possibly derived from the diploids D. fladnizensis, D. nivalis and (or) D. subcapitata. In extensive analyses they found that the intrapopulational isozyme variation was low or absent, the diploids were almost invariably homozygous, and D. lactea was highly fixed heterozygous. Multivariate analyses of the RAPD data revealed four very distinct groups of multilocus phenotypes. These groups also differed in several morphological characters and corresponded to the four tentative species. The species were less differentiated in isozyme loci, in particular the diploids D. fladnizensis and D. subcapitata, but D. lactea was clearly distinguished from D. fladnizensis based on all three data sets.
Illustrations. • Close-up of fruiting plant. Plant growing in rock crevice, a common habitat for this species. Note that the stem and siliques are glabrous and the siliques are narrowly elliptic. The species may have 1 or no leaves on the flowering stem, but usually there is 1. Russia, Altai. Hanne H. Grundt. 2000. pop. no 110 Oslo O. Photograph by Hanne H. Grundt. • 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..