Perennial. Main stems erect, 20-45 cm tall; branches lf-opposed, spreading, ridged, ± densely covered with fine, short, backward-pointed hairs. Basal lvs withering at fruiting; early lvs glabrous; later lvs sparsely bristly above and beneath; margins with triangular or 2-lobed cartilaginous denticles; lamina narrow-oblancolate, pinnate, 6-12-(20) × 1.5-2.5-(4) cm; pinnae in (3)-5-8 pairs, toothed, especially on distal margin. Stem lvs becoming simple, bristly; margins with small triangular or 2-lobed cartilaginous denticles; middle lvs narrow-oblanceolate, toothed, cuneate at base, 1.5-3 × 0.5-1.5 cm; upper lvs narrow-oblong, toothed or 3-fid at apex, 5-15 × 2-4 mm, abruptly narrowed or sub-auriculate at very shortly stalked base. Racemes (3)-5-10 cm long; rachis and pedicel hairs as on stems; pedicels erecto-patent to patent, 3-4 mm long at fruiting. Sepals glabrous or sparsely hairy, often purplish with scarious margin, 0.7-1 × c. 0.5 mm. Petals white, much < sepals. Stamens 2. Silicles ovate, 2.7-3 × 2-2.3 mm; stigma almost sessile in shallow notch; valves usually purple, glabrous or sparsely hairy. Seed narrow-ovoid, brown, not winged, c. 1.5 mm long.