E-Flora BC: Electronic Atlas of the Flora of British Columbia

General:
Annual herb; stems erect, 10-80 cm tall, simple or few-branched, somewhat 4-angled, nearly smooth to thinly soft-hairy at the nodes and in lines down opposite 2 of the 4 sides.

Leaves:
Opposite, unstalked, lanceolate to oblong, 1-5 cm long, prominently toothed, rough appressedhairy.

Flowers:
Inflorescence a leafy-bracted, terminal, spike-like cluster of several to many, nearly unstalked flowers; corollas yellow, tubular, 10-15 mm long, 2-lipped, the upper lip hood-like and usually with a pair of short, broad, often purplish teeth near the tip, the lower lip 3-lobed; calyces membranous, 7-10 mm long in flower, to 12-17 mm and much inflated in fruit, like a flattened net-veined balloon, 4-toothed, the teeth fine-hairy; stamens 4, the anthers hairy.

Fruits:
Capsules, nearly globe-shaped, flattened, 8-15 mm long, enveloped by the calyx-balloon; seeds several, large, 3-6 mm in diameter, flat, narrow-winged.

Notes:
A murky species complex but it appears that in BC only 1 entity is present.