Artemisia tripartita subsp. tripartita

Treatment appears in FNA Volume 19. Treatment on page 518.

Shrubs, 20–150(–200) cm. Leaves 1.5–4 × 0.5–1.5 cm, lobes linear, to 0.5 mm wide. Heads in spiciform arrays (6–)8–15(–35) × (1–)4–5 cm. Involucres 2–3 × 2 mm. Florets 4–8. Cypselae 1.8–2.3 mm. 2n = 18, 36.


Phenology: Flowering mid summer–late fall.
Habitat: Deep loam soils, usually igneous in origin
Elevation: 900–1900 m

Distribution

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B.C., Idaho, Nev., Oreg., Wash., Wyo.

Discussion

Subspecies tripartita ranges throughout the Snake River and Columbia River basins, extending north through central British Columbia, where average annual precipitation is 375–800 mm. Because much of the range includes fertile agricultural land, much of the habitat has been lost to farming, and populations of subsp. tripartita occur as isolated islands along drainages and at the bases of mountain slopes. It may be one of the parents involved in the presumed hybrid origin of Artemisia arbuscula subsp. thermopola.

Selected References

None.

Lower Taxa

None.

Leila M. Shultz +
Rydberg +
Artemisia trifida +
B.C. +, Idaho +, Nev. +, Oreg. +, Wash. +  and Wyo. +
900–1900 m +
Deep loam soils, usually igneous in origin +
Flowering mid summer–late fall. +
Mem. New York Bot. Gard. +
Illustrated +  and Endemic +
Artemisia tridentata subsp. trifida +  and Seriphidium tripartitum +
Artemisia tripartita subsp. tripartita +
Artemisia tripartita +
subspecies +