15. Erysimum pallasii (Pursh) Fernald, Rhodora. 27: 171. 1925.
Cheiranthus pallasii Pursh, Fl. Amer. Sept. 2: 436. 1813; C. pygmaeus Adams; Erysimum pallasii var. bracteosum Rossbach; E. pygmaeum (Adams) J. Gay; Hesperis hookeri Ledebour
Perennials; (caudex simple or branched, covered with persistent leaf bases). Trichomes of leaves 2-rayed. Stems erect, unbranched, (0.1-)0.4-4 dm. Basal leaves: blade linear to narrowly linear-oblanceolate, 3-5 cm × 1-2 mm, base attenuate, margins entire or denticulate. Cauline leaves: blade reduced distally, often as bracts. Racemes (sometimes bracteate basally), elongated in fruit. Fruiting pedicels divaricate to ascending, slender, narrower than fruit, (4-)7-24(-35) mm. Flowers: sepals oblong or narrowly so, 5-9 mm, lateral pair slightly saccate basally; petals usually purple, rarely lilac, oblanceolate to broadly obovate, 10-20 × 3-5 mm, claw 5-9 mm, apex rounded; median filaments 6-9 mm; anthers narrowly oblong, 1-1.5 mm. Fruits erect to divaricate-ascending, narrowly linear, straight or curved inward, not torulose, (3-)5-11(-13) cm × 2-4 mm, latiseptate, not striped; valves with prominent midvein, pubescent outside, trichomes 2-rayed, glabrous inside; ovules (28-)36-74 per ovary; style cylindrical, stout, 0.5-3 mm, sparsely pubescent; stigma strongly 2-lobed, lobes as long as wide. Seeds oblong, 1.7-2.2 × 0.9-0.1.4 mm; not winged. 2n = 24, 36.
Flowering Jun-Aug. Cliffs, shaley slopes, talus, sandy ground, alpine areas, clay banks, pebbles, gravel; 0-1300 m; Greenland; N.W.T., Nunavut, Yukon; Alaska; e Asia (Russian Far East).
R. C. Rollins (1993) and G. A. Mulligan (2002) listed haploid chromosome numbers of n = 12, 14, 18, and 21 for Erysimum pallasii, but it is doubtful that those deviating from x = 6 are correct. Tetraploid counts (2n = 24) are known from both Canada and Russian Far East, whereas hexaploid counts are known only from the latter region. G. B. Rossbach (1958) and Rollins recognized plants with racemes bracteate to the middle as var. bracteosum, but this distinction is rather artificial, and the species shows considerable variation in the number of bracteate flowers.