Small annual herb from a taproot; stems decumbent to erect, 5-25 cm tall, simple or more often freely branched, nearly smooth to minutely hairy.
Opposite, stalked, broadly egg- to diamond-shaped, 1-4 cm long, irregularly toothed, yellowish-green, smooth, obscurely 3- to 5-veined from the base; the stalks at least as long as the blades.
Inflorescence of few to several long-stalked flowers in the axils of the leaves, the stalks slender, 7-25 mm long, usually longer than the subtending leaves, spreading to ascending; corollas tubular funnel-shaped, 7-14 mm long, yellow with a large reddish blotch within at the base of the lower lip, smooth, 2-lipped, the upper lip with 2 erect lobes, the lower lip 3-lobed, the middle lobe spreading to deflexed and nearly twice as long as the lateral lobes; calyces 4-7 mm long, smooth or minutely hairy, 5-toothed, the 2 lower teeth rounded and longer than the 3 tiny, sharply triangular, upper teeth; stamens 4, smooth.
Capsules, oblong, pointy-tipped, 5-7 mm long; seeds numerous.
Source: The Illustrated Flora of British Columbia