General:
Annual herb from fibrous roots; sparsely to moderately straight appressed-hairy, also sometimes with slender spreading hairs; stems simple or branched, 10-40 cm tall.

Leaves:
Basal leaves nearly lacking; stem leaves oblong to linear, entire, 0.5-8 cm long, 3-8 mm wide, the lower 2-4 pairs opposite, the others alternate.

Flowers:
Inflorescence of several coiled, narrow, elongating, often paired spikes that lack bracts; flowers relatively large and showy; petals white, fused at base into a tube that spreads (5-10 mm wide) abruptly at top to 5 lobes, the throat with 5 yellow bulges; fruiting calyces 3-4 mm long, densely ascending-hairy.

Fruits:
Nutlets 4 (or fewer by abortion), egg-shaped, 1.2-1.7 mm long, wrinkled-pimply on both sides.

Source:  The Illustrated Flora of British Columbia