Braya thorild-wulffii Ostenf.
Brassicaceae (Cruciferae), Draba family.
Meddel. Gronland 64: 176. 1923
Braya pilosa Hooker subsp. thorild-wulffii (Ostenf.)
V.V.Petrovsky in Tolm., Fl. Arct. URSS 7: 52. 1975.
Braya
purpurascens (R.Br.) Bunge subsp. thorild-wulffii (Ostenf.)
Hultén, Kongl. Sv. Vetensk.-Akad. Handl. 13, 1: 1. 1971.
Braya pilosa Hook. subsp. thorild-wulffii (Ostenf.)
V.V.Petrovsky in Tolm. (1975), Fl. Arct. URSS 7: 52. 1975.
Braya
purpurascens (R.Br.) Bunge subsp. thorild-wulffii (Ostenf.)
Hultén, Kongl. Sv. Vetensk.-Akad. Handl. 13, 1: 18. 1971.
Braya
purpurascens (R. Br.) Bunge var. thorild-wulffii (Ostenf.) Boivin
Vegetative morphology. Plants perennial herbs; (3–)5–9(–14) cm high; caespitose; tufted with mainly basal leaves and decumbent flowering stems, silques ovoid 1.5–2 times as long as broad. Taproot present. Caudex present. Ground-level or under-ground stems vertical and often branched. Vegetative, aerial, stem a small transition zone between roots and basal leaves, or vegetative stem a small transition zone between roots and branches arising at ground-level; aerial stems decumbent, or prostrate; aerial stems sparsely hairy, or densely hairy (unbranched and 2-forked villous hairs); aerial stem hairs spreading, or erect. Leaves in a basal tuft, or basal in a rosette. Leaves erect (stems decumbent). Leaves alternate; simple; existing for a single season or less and marcescent (slightly). Petioles absent. Leaf blade bases attenuate. Blades 10–14 mm long; 3–4 mm wide. Blades appressed to the stem, or spreading; herbaceous; oblanceolate (linear spathulate); appearing single-veined, or with inconspicuous veins. Blades adaxial surface glabrous (on the surface), or hairy (often with a tuft of hairs on the margin at the apex). Blades adaxial surface hairs white and translucent. Blades abaxial surface glabrous. Blade margins not lobed. Blade margins entire; with non-glandular hairs (that are long and mostly simple, often with a t uft of hairs at the apex). Leaf apices rounded.
Reproductive morphology. Flowering stems present. Flowering stems conspicuously taller than the leaves (usually), or shorter than the leaves (B. thoridl-sulfii when stems are prostrate); without leaves (usually), or with leaves (rarely, and then only a single leaf); hairy. Flowering stem hairs woolly; simple (mainly); white or translucent. Inflorescence racemose; dense (in flower), or diffuse (in fruit); elongating as the fruit matures; main axis hairy. Pedicels present; with non-glandular hairs. Flowers per inflorescence 3–6(–9); small, less than 5 mm in diameter or length; actinomorphic. Calyx sepals 4; free; 2.5–3 mm long; 1–2 mm wide (obtuse, piloose or glabrous). Calyx purple; hairy; woolly. Calyx hairs white or translucent. Calyx margins ciliate (sometimes, as a tuff of hairs at the tip). Petals free; same length as the calyx, or longer than the calyx; 4; white, or pink, or purple (tinged); without contrasting markings; obovate (tapering gradually from the base to the apex); unlobed; 2–3.7 mm long; 1–1.5 mm wide. Stamens 6; filaments markedly unequal in length; free of the corolla; filaments glabrous. Anthers yellow; ovoid; 0.4–0.6 mm long. Gynoecia superior. Carpels syncarpous; 2. Ovaries ovate; hairy; woolly. Ovary hairs white, or translucent; appressed; wavy, or branched (2-forked). Styles present (sometimes only just); 1; completely fused; thick and short; 0.75–1 mm long. Stigmas per style 1 (sometiems braodly bilobed); plate shaped. Placentation parietal. Ovules 12–26. Fruit stalked; stalk (1–)2.5–4 mm long. Fruit without calyx persisting; dry; a silique; ovoid; not distinctly flattened; dehiscent. Fruit (4–)5–8(–10) mm long; (2.5–)3–5 mm wide; yellowish, or purple (grey from the hairs); hairy (densely pubescent with unbranched and 2-forked hairs); surface appearing veinless. Styles persisting in fruit 0.75–1 mm long (short, almost obsolete). Seeds (12–)18–26; (0.9–)1–1.2(–1.4) mm long; brown, or yellowish; with surfaces smooth.
Chromosome information. 2n = 28. 28 (4x). - Holmen (1952 Greenland); Jakobsen in Sørensen et al. (1956 Greenland); Mulligan (1965a Can?); Böcher (1966a Greenland). Ploidy levels recorded 4x.
Distribution. Northern hemisphere distribution: North American; Greenland, Canada, Asia (Wrangel Island and possibly on mainland north eastern Aisa). Northwest Territories Islands, Continental Northwest Territories, Nunavut Islands, Continental Nunavut, Northern Québec. High arctic. Range in the Canadian Arctic Archipelago limited. Uncommon. Arctic Islands: Ellesmere, Axel Heiberg, Parry Islands (Bathurst and Prince Patrick), Cornwallis, Banks, Victoria (Stefansson Is.).
Ecology and habitat. Substrates: river terraces, slopes, cliffs; imperfectly drained moist areas, or dry, or moderately well drained areas; acidic, or calcareous; gravel, sand, clay, till; with low organic content. Habitats: grows on dry substrates, often on south-facing slopes; on well drained drumlin crests (CAN 522694); colonizing species on well to moderately well drained silt (CAN 533007); mosit clay on stony plain (CAN 223286).
Notes. Braya thorild-wulffii differs from B. purpurascens both in several morphological characters and in ploidy level. We propose to treat it as a distinct species. Plants from Wrangel Island are confirmed as belonging to this species and are geographically connected to the 'type' area in Greenland by later finds through arctic Canada. (Petrovsky, Murray & Elven, in ELeven et al. 2002).
Illustrations. • Type specimen. Holotype of Braya thorild-wulffii var. glabrata. N.W.T., Banks Island, Bernard River, 73 22 N, 121, 47 W W.J. Maher and S. MacLean, 139. 6 Aug. 1963. CAN 279211. • Arctic Island Distribution.
Cite this publication as: ‘S.G. Aiken, M.J. Dallwitz, L.L. Consaul, C.L. McJannet, L.J. Gillespie, R.L. Boles, G.W. Argus, J.M. Gillett, P.J. Scott, R. Elven, M.C. LeBlanc, A.K. Brysting and H. Solstad. 1999 onwards. Flora of the Canadian Arctic Archipelago: Descriptions, Illustrations, Identification, and Information Retrieval. Version: 29th April 2003. http://www.mun.ca/biology/delta/arcticf/’. Dallwitz (1980) and Dallwitz, Paine and Zurcher (1993, 1995, 2000) should also be cited (see References).
