General:
Annual or biennial herb from a slender taproot; stems prostrate to ascending, several, few branched above, glabrous to short-hairy, 2.5-15 cm tall/long.

Leaves:
Basal and stem leaves opposite, awl-like, 5-20 mm long, slightly papery-margined near their shortly fused bases; stipules lacking.

Flowers:
Inflorescence of solitary flowers in stem forks, or in a terminal or axillary cluster; petals lacking; sepals usually 5, fused for 1/2 their length into a bell-shaped, 10-nerved tube, green or whitish, the lobes lanceolate, abruptly sharp-pointed, 1.5-2 mm long, glabrous.

Fruits:
Inflated bladders, egg-shaped, 1-seeded, enclosed by the hardened calyx tube.

Source:  The Illustrated Flora of British Columbia