Distribution: Distributed on both sides of the Cascades in Washington; Alaska south to California, eastern North America.
Habitat: Swamps, lakes and ditches.
Flowers: May-July
Origin: Native
Conservation Status: Not of concern
Erect, glabrous herbs from creeping rhizomes, the flowering stems 2-8 cm. tall, with fine, purplish-black spots almost throughout.
Lowermost leaves sessile and greatly reduced; upper leaves opposite, nearly sessile, linear-lanceolate to narrowly elliptic, long-acuminate, up to 15 cm. long, narrowed gradually to the base.
Flowers crowded and sub-sessile in dense, slender, pedunculate racemes in the axils of 2 or 3 pairs of larger leaves near mid-stem; calyx lobes 5, united only at the base, spotted, glabrous, lanceolate, 2-3 mm. long; corolla divided nearly to the base, the 5 lobes linear-lanceolate, pale yellow, twice the length of the calyx; stamens 5, exerted, opposite the corolla lobes, the filaments distinct, glabrous.
Capsule 2.5 mm. long, spotted, opening by 5 valves.
PNW Herbaria: Specimen records of Lysimachia thyrsiflora in the Consortium of Pacific Northwest Herbaria database.
WA Flora Checklist: Lysimachia thyrsiflora checklist entry.
E-Flora BC: Lysimachia thyrsiflora atlas page.
CalPhotos: Lysimachia thyrsiflora photos.
USDA Plants: Lysimachia thyrsiflora information.