Description from Flora of China
Cheiranthus caspicus Lamarck in Pallas, Voy. [Reise Russ. Reich., French Transl. 2] 8: 348. 1794; C. tomentosus Willdenow; Sterigmostemum tomentosum (Willdenow) Marschall von Bieberstein.
Plants perennial, (6-)10-25(-30) cm tall, tomentose, with woody caudex. Trichomes dendritic; glandular trichomes absent. Stems several from base. Basal leaves green or canescent; petiole 0.5-2 cm; leaf blade linear, lanceolate, or obovate, (3-)4-8(-13) cm × 5-10 mm, base attenuate, margin entire, obtusely sinuate-dentate, pinnatifid, or pinnatisect and with entire, dentate, or lobed lateral segments, apex subacute. Uppermost cauline leaves subsessile, smaller, often undivided. Fruiting pedicels thickened, divaricate, (2-)5-12(-17) mm. Sepals oblong, (2.5-)3-4(-5) × 0.5-1 mm, lateral pair broader. Petals yellow, (5-)6-8(-9) × 2.5-3.5 mm, base attenuate into a claw. Median filament 5-6 mm, united to middle or slightly above; lateral filaments 3.5-4 mm; anthers 2-2.5 mm. Ovules 20-40 per ovary. Fruit linear, (2-)3.5-5.5(-6.5) cm × 1.5-2.2 mm, divaricate to divaricate-ascending, straight or curved; valves thickened, tomentose; style 1-3 mm, thickened; stigma lobes erect to subconnivent. Seeds brown, oblong, 2-2.5 × 0.6-0.8 mm. Fl. Apr-Jun, fr. May-Jul.
The record in FRPS of Sterigmostemum incanum Marschall von Bieberstein is based on misidentified plants of Oreoloma violaceum. The former species is restricted to SW Asia and adjacent Caucasus. The records of S. tomentosum in FRPS and Fl. Xinjiang. (2(2): 184. 1995) from Xinjiang are likely based on misidentified plants of O. eglandulosum or perhaps refer to S. caspicum. The last species is common in Kazakhstan but is very rare in China. The only Chinese collection of S. caspicum examined by the present authors is Anonymous 1840 (K, LE), collected from "Songaria Chin. ad lacum Saisang-Nor." It represents the easternmost known range of the species.
Steppe, deserts, arid areas; 500-1200 m. Xinjiang [Kazakhstan, Russia].