Description from Flora of China
Sisymbrium axillare J. D. Hooker & Thomson, J. Proc. Linn. Soc., Bot. 5: 162. 1861; Guillenia axillaris (J. D. Hooker & Thomson) Bennet; G. bracteosa (Jafri) H. B. Naithani & S. N. Biswas; Microsisymbrium axillare (J. D. Hooker & Thomson) O. E. Schulz; M. axillare var. brevipedicellatum Jafri; M. axillare var. dasycarpum O. E. Schulz; M. bracteosum Jafri.
Herbs annual or perennial, (3-)10-20 cm tall. Stems decumbent or ascending, few to many branched at base, densely hispid with coarse, horizontal, simple trichomes to 2 mm, these often mixed with coarse, forked, much smaller, stalked stellate ones, rarely glabrescent distally. Basal leaves rosulate, petiolate, often withered by fruiting; petiole (0.2-)1-2 cm, often ciliate; leaf blade spatulate, (0.6-)1-3.5(-5) × (0.2-)0.5-1.5 cm, pubescent with stalked, forked trichomes mixed with larger, forked or simple ones, margin coarsely dentate, sinuate, or lyrate-pinnatifid, apex obtuse. Middle cauline leaves broadly oblong, elliptic, or obovate, sessile, 1-2.5 × (0.2-)0.7-1.3 cm, pubescent as basal leaves, rarely glabrescent, base cuneate, not auriculate, margin dentate, apex acute. Racemes bracteate along entire length. Fruiting pedicels slender, stellate pubescent laterally and abaxially, glabrous adaxially or rarely all around, divaricate or ascending, (2.5-)4-10(-12) mm. Sepals narrowly oblong, 2-3 × 0.6-1 mm, coarsely pubescent. Petals white or pink, spatulate, 3-4.5 × (0.8-)1-1.2 mm, attenuate to base; claw to 1 mm. Filaments 2-3 mm; anthers oblong, 0.4-0.6 mm. Ovules 60-90 per ovary. Fruit linear, terete, curved upward or sometimes straight, divaricate, (1.4-)2.5-4(-5) cm × 0.6-0.8 mm; valves glabrous or rarely puberulent, with an obscure midvein; style (0.1-)0.4-1 mm. Seeds brown, oblong, 0.8-1 × 0.3-0.4 mm. Fl. Mar-Jun, fr. May-Jul.
Rocky hillsides, shady banks, open woodlands, roadsides, rock crevices, terraces, forests; 2200-3000 m. Xizang [Bhutan, India, Kashmir, Nepal, Sikkim].