Erysimum siliculosum (M. Bieb.) DC.

The record of Erysimum vassilczenkovii Polatschek in FRPS (as Syrenia macrocarpa Vassilczenko, not E. macrocarpum (Ruprecht) Stevens & Trautvetter (1883)) is very likely based on misidentified plants of E. siliculosum. The record of E. sessiliflorum R. Brown in Fl. Xinjiang. (2(2): 199. 1995, as Syrenia sessiliflora (R. Brown) Ledebour) is based on misidentified plants of E. siliculosum with slightly shorter fruiting pedicels.

Herbs biennial or perennial, 30-90(-100) cm tall. Trichomes malpighiaceous throughout, mixed with 3-forked ones on calyx. Stems erect, often branched at base and above. Basal leaves rosulate, often persisting, petiolate; leaf blade filiform to linear, rarely linear-oblanceolate, 1.5-8 cm × 1-2(-5) mm, longitudinally folded, base narrowly attenuate, margin entire, apex acute. Cauline leaves similar to basal. Racemes corymbose, densely flowered, ebracteate or rarely lowermost few flowers bracteate, elongated considerably in fruit. Fruiting pedicels ascending or divaricate-ascending, (2-)4-6 mm, stout, narrower than fruit. Sepals oblong-linear, (6-)7-9(-10) × 1-2 mm, united, persistent well after fruit maturity, strongly saccate. Petals bright yellow, obovate or broadly spatulate, (1.1-)1.4-1.8(-2) cm × 5-8 mm, apex rounded; claw distinct, subequaling sepals. Filaments yellow, 6-10 mm; anthers linear, 2-3 mm. Ovules 50-100 per ovary. Fruit oblong to oblong-linear, strongly 4-angled, slightly angustiseptate, (5-)7-10(-14) × 2-3 mm, smooth, erect and often appressed to rachis, straight; valves with a prominent midvein and slightly winged keel, outside with transversely oriented malpighiaceous trichomes, inside glabrous; style slender, (4-)5-10(-12) mm, cylindric; stigma strongly 2-lobed, with lobes often divergent. Seeds oblong, 1.1-1.4 × 0.7-0.9 mm. Fl. May-Jun, fr. Jun-Jul. 2n = 14.

Xinjiang [Kazakhstan, Russia, Turkmenistan].

Sandy areas, dunes; 400-1400 m.

Cheiranthus siliculosus Marschall von Bieberstein, Fl. Taur.-Caucas. 2: 121. 1808; Syrenia siliculosa (Marschall von Bieberstein) Andrzejowski.