Description from Flora of China
Hesperis elata Hornemann; H. matronalis Linnaeus var. elata (Hornemann) Schmalhausen; H. matronalis subsp. sibirica (Linnaeus) G. V. Krylov; H. matronalis var. sibirica (Linnaeus) de Candolle; H. oreophila Kitagawa; H. pseudonivea Tzvelev; H. sibirica var. alba Georgi.
Herbs perennial or biennial, (25-)40-100(-140) cm tall, often densely glandular especially above, hirsute with simple trichomes to 3 mm. Stems erect, simple basally, often branched above, glandular and often also subsetose. Basal leaves withered by flowering. Middle and upper cauline leaves narrowly to broadly lanceolate, (3-)5-10(-16) × (0.5-)1-3.5(-5.5) cm, sessile or subsessile, glandular and with simple trichomes, base cuneate, margin denticulate or subentire, apex acute or acuminate. Fruiting pedicels divaricate or ascending, 0.7-2.5(-3.2) cm, glandular. Sepals narrowly oblong, 5.5-7.5(-10) × 1.5-2 mm. Petals deep purple, lavender, or white, narrowly to broadly obovate, 1.5-2(-2.5) cm × 5-10 mm, apex rounded; claw 7-10 mm. Filaments 3-5.5(-6.5) mm; anthers linear, 2.5-4 mm. Fruit terete, (3-)4-10(-13) cm × 1.5-2 mm; valves sparsely to densely glandular, constricted between seeds. Seeds oblong, (1.5-)2-2.7(-3) × 1-1.3 mm. Fl. and fr. May-Sep. 2n = 14.
The alleged differences between Hesperis sibirica (petals purple, 15-24 mm) and H. pseudonivea (petals white, 18-23 mm) do not support their recognition as independent taxa at any rank because white flowers can be found in many populations of H. sibirica, and there are no other characters that separate the two.
Mountains slopes, shrubby areas, plains, near rivers; 900-2900. Hebei, Liaoning, Xinjiang [Kazakhstan, Kyrgyzstan, Mongolia, Russia, Tajikistan, Uzbekistan].