Braya purpurascens (R.Br.) Bunge
Brassicaceae (Cruciferae), Draba family.
Fl. Ross. 1: 195.1842.
Platypetalum purpurascens R.Br., Chlor. Melvill. 9.1823
Type: Described from Northern Canada: Melville Island. Type probably in BM.
Braya glabella Richardson subsp. purpurascens (R.Br.) Cody,
Canad. Field.-Natural. 108: 93. 1964.
Braya henryae Raup, Contr.
Arnold Arbor. 6: 167. 1934
Vegetative morphology. Plants perennial herbs; 3.5–10.5(–12.8) cm high; caespitose; simple, decumbent to prostrate or occasionally ascending flowerings stems, leaves with long hairs on the margins and often with a tuft of hairs at the apex, siliques 3–5 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 erect, or ascending; aerial stems glabrous, or sparsely hairy; aerial stem hairs appressed, or spreading. Leaves in a basal tuft (older plants), or basal in a rosette. Leaves erect. Leaves alternate; simple; existing for a single season or less. Petioles absent. Leaf blade bases truncate, or attenuate. Blades 10–40 mm long; 0.6–1.2 mm wide. Blades appressed to the stem, or spreading; succulent (slightly); linear and oblanceolate; with inconspicuous veins. Blades adaxial surface shiny (see image library); glabrous. Blades abaxial surface glabrous. Blade margins entire; glabrous, or with glandular hairs. Leaf apices acute, or rounded.
Reproductive morphology. Flowering stems with leaves (occassionally), or without leaves; glabrous (almost), or hairy (with tangled stiff trichomes). Flowering stem hairs simple, or branched; white or translucent. Inflorescence racemose (capitate at first but soon elongating); dense (in flower), or diffuse (in fruit); elongating as the fruit matures; main axis hairy. Pedicels glabrous (almost), or with non-glandular hairs. Flowers per inflorescence 5–12; small, less than 5 mm in diameter or length. Calyx sepals 4; free; 2–3.5 mm long; 1–1.5 mm wide. Calyx green, or purple, or pink; glabrous, or hairy (very sparsely); pilose. Calyx hairs white or translucent. Petals free; 4; white, or pink (purplish tinged); without contrasting markings; spatulate; unlobed; 2.9–3.1 mm long; 2–2.5 mm wide (at wide apex: 0.4–0.6 at base). Stamens 6; filaments markedly unequal in length; free of the corolla; filaments glabrous. Anthers yellow; subglobose; 0.4–0.6 mm long. Gynoecia superior. Carpels syncarpous; 2. Ovaries pear-shaped; hairy; woolly (with tangled stiff hairs). Ovary hairs white, or translucent; spreading; straight (and very short, about 0.2 mm long). Styles present (but very short); 1; completely fused; thick and short; 0.1–0.2 mm long. Stigmas per style 1; plate shaped. Placentation parietal. Ovules 5–20. Fruit stalked; stalk 2–4 mm long. Fruit without calyx persisting; dry; a silique; elongate-cylindrical (plump, somewhat torulose); not distinctly flattened; dehiscent. Fruit 14–17 mm long; 8–9 mm wide; yellowish (green); hairy; surface venation ribbed (slightly). Seeds 5–20; 0.9–1.1 mm long; brown; with surfaces smooth.
Chromosome information. 2n = 48, 56, 64, and 84. 48. -
Zhukova and Petrovsky (1984 north and north eastern Asia).
56
(8x). - Holmen (1952 Greenland, the arctic entity); Löve and
Löve 1956 Jørgensen et al. (1958 Greenland, the arctic entity);
Mulligan (1965b central Alaska, the 'henryae' entity); Böcher
(1966a); Zhukova (1966 Wrangel Island); Johnson and Packer (1968 northwestern
Alaska , the arctic entity); Zhukova and Petrovsky (1971 Wrangel Island, the
arctic entity); Zhukova et al. (1973 north eastern Asia, the arctic entity);
Dawe and Murray (1979 northern Alaska, the arctic entity); Petrovsky and Zhukova
(1981 Wrangel Isl., the arctic entity); Zhukova and Petrovsky (1984 north
eastern Siberia, 1987a, the arctic entity).
64. - Sørensen and
Westergaard in Löve & Löve (1948 Greenland).
84 (12x).
- Krogulevich (1976 northern Siberia, Putorana). Ploidy levels recorded
8x&12x.
Notes. Rollins (1993) synonymised B. glabella, B.
purpurascens (and B. henryae), and B. bartlettiana without any
arguments and without reference to other authors. It is difficult both to object
to and to accept his point of view without comparison of types of all four
entities.
Braya henryae was accepted as a species by Porsild &
Cody (1980) albeit with some doubts: "perhaps should be considered a
geographical race of that species [i.e., B. purpurascens]; thus far it is
known only from the eastern slope of Richardson and Mackenzie Mountains". It was
included in the synonymy of the extended B. glabella sensu Rollins
(1993), also including B. purpurascens. We have temporarily placed the
name in synonymy of B. purpurascens as we now have compared typical
material of both species, as proposed by Petrovsky. Plants that confirm with the
description of B. henryae are fairly frequent in mountains in central
Alaska and Yukon (Alaska). They differ slightly from B. purpurascens in
the Arctic in a few quantitative characters, but in our opinion not enough to
merit rank as a separate species. Some combined morphological and genetical
investigation should be undertaken before their appropriate rank (possibly as
subspecies) is decided. (Murray & Elven in Elven et al. 2002).
Illustrations. • Plant habitat. Calcareous loam on upper beach with scattered plants. Norway: Svalbard, Gipsdalen. Aug. 1997. Photo: R.Elven. • Braya purpurascens. Close-up of flowering plant. Plant growing in clayey soils on river fan. Norway: Svalbard, Gipsdalen. Aug. 1997. Photographed by R.Elven. • Braya purpurascens. Close-up of flowering plant. Large flowering plant with characteristic pale lilac petals. Norway: Svalbard, Gipsdalen. 24.07.1985. Photographed by R.Elven. Voucher in HbTROM. • Braya purpurascens. Close-up of flowering plant. Plant growing in calcareous loam on beach terrace. Norway: Svalbard, Gipsvika. July 1997. Photographed by R.Elven. • Braya purpurascens. Close-up. Flowering plant with last year's infrutescences. Note the short, thick fruits separating this from B. glabella s.str. Norway: Svalbard, Gipsdalen. Aug. 1997. Photographed by R.Elven. • Braya purpurascens. Close-up. Flowering plant in calcareous loam. Norway: Svalbard, Gipsdalen. July 1997. Photographed by R.Elven.
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).
