Description from Flora of China
Sisymbrium deltoideum J. D. Hooker & Thomson, J. Proc. Linn. Soc., Bot. 5: 163. 1861; Eutrema deltoideum var. grandiflorum O. E. Schulz; Hesperis deltoidea (J. D. Hooker & Thomson) Kuntze.
Herbs (7-)20-75(-110) cm tall, sparsely pilose or glabrous; rhizomes short. Stems erect, simple at base, branched above. Basal leaves rosulate, somewhat fleshy; petiole (1.5-)3.5-10(-15) cm; leaf blade ovate, deltoid, or oblong, (1-)2-5(-8) × (0.5-)1-3(-5) cm, base cordate or rounded, margin dentate or rarely subentire, apex obtuse or subacute. Middle cauline leaves with petioles (0.3-)1-2.5(-3.5) cm; leaf blade broadly ovate, ovate-deltoid, or rhomboid, (1.5-)3-6(-10) × (0.3-)2-4.5(-6) cm, palmately veined, base truncate or cordate, margin dentate, apex obtuse or acute. Infructescence lax raceme, main branch 6-15 cm. Fruiting pedicels ascending or suberect, 5-1.2(-15) mm. Sepals ovate, 2-3 × 1.5-2.5 mm, caducous. Petals white or pink, spatulate or obovate, (5-)6-8 × 2.5-4 mm. Filaments white, 1.5-2.5 mm, slightly dilated at base; anthers oblong, 0.5-1 mm. Ovules 2-4 per ovary. Fruit lanceolate, oblong, or ovoid, 7-10 × 2-3 mm, often subappressed to rachis, slightly 4-angled, not torulose; valves with a prominent midvein; gynophore to 1 mm; septum perforated or complete; style obsolete or to 1 mm. Seeds oblong, plump, 2.5-3.5 × 1-1.5 mm. Fl. Jul-Aug, fr. Aug-Sep.
The fruit shape and dimensions given for Eutrema deltoideum in all Chinese floras are based on misidentified plants of E. himalaicum. Eutrema deltoideum var. grandiflorum has slightly larger flowers than those of the type, but these represent extremes of a continuous variation. The species was recorded from Sichuan in FRPS and in Fl. Sichuan. (14: 155. 1999), but the present authors have seen no material from that province.
Rock crevices, among shrubs, steep slopes, moist meadows, Betula-Rhododendron forests, streambeds; 3600-4700 m. Xizang, Yunnan [Bhutan, Sikkim].