Stems usually ascending (prostrate in fruit), unbranched, 0.3-1.6 dm, moderately pubes-cent. Leaves: blade margins pinnatifid or entire, surfaces moderately pubescent. Flowers: petals white or purple-tinged, (3-)4-5.6 × (1.3-)2-3.3(-3.8) mm. Fruits usually fertile and fully developed, not or weakly torulose, (1-) 1.2-1.8(-2) mm wide; septum often fenestrate (with circular perforations at regular intervals longitudinally or with a narrow, elliptical, longitudinal split at base or both). 2n = 42.

Flowering Jun-Jul, fruiting Jul-Aug. Sand, clay, and gravel slopes and plains; 0-200 m; Nunavut.

Prostrate fruiting stems, exceptionally broad, non-torulose fruits, and fenestrate silique septae distinguish subsp. ellesmerensis from other subspecies of Braya humilis. It is known only from northern Ellesmere Island.