Erysimum siliculosum is a biennial or perennial herb from Xinjiang, Kazakhstan, Russia, and Turkmenistan, reaching 30âÂÂ90 cm in height. It is closely related to Erysimum mongolicum. This species inhabits sandy areas and dunes from 400 to 1400 m of altitude.
Erysimum siliculosum produced 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, 1.5âÂÂ8 cm à1-2(-5) mm, longitudinally folded, base narrowly attenuate, margin entire, apex acute. Cauline leaves similar to basal.
Erysimum siliculosum flowers from May to July, depending on the altitude.
Racemes are corymbose, densely flowered, ebracteate or rarely lowermost few flowers bracteate, elongated considerably in fruit. Fruiting pedicels are ascending or divaricate-ascending, (2-)4âÂÂ6 mm, stout, narrower than fruit. Sepals are oblong-linear, (6-)7-9(-10) à1âÂÂ2 mm, united, persistent well after fruit maturity, strongly saccate.
Petals are bright yellow, obovate or broadly spatulate, (1.1-)1.4-1.8(-2) cm à5âÂÂ8 mm, apex rounded; claw distinct, subequaling sepals. Filaments yellow, 6âÂÂ10 mm; anthers linear, 2âÂÂ3 mm. Ovules 50-100 per ovary.
Fruit are oblong to oblong-linear, strongly 4-angled, slightly angustiseptate, (5-)7-10(-14) à2âÂÂ3 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 are oblong, 1.1-1.4 à0.7-0.9 mm. 2n = 14.