Artemisia tripartita subsp. rupicola
Rhodora 61: 82. 1959.
Shrubs, 5–15 cm. Leaves 1.5–3.5 × 1–2 cm; lobes lanceolate, 1–1.5 mm wide. Heads in paniculiform arrays (5–) 8–12 (–15) × (0.5–) 1–3 cm. Involucres 2–4 × 1.5–3 mm. Florets 3–11. Cypselae 1.8–2 mm.
Phenology: Flowering early–late summer.
Habitat: Shallow rocky soils, grasslands
Elevation: 2500–2900 m
Subspecies rupicola is known only from the high, windy plains of south-central Wyoming. The continental divide separates subsp. tripartita to the west and subsp. rupicola to the east. Because of its limited distribution and scant representation in herbaria, this distinct morphologic form escaped notice until it was described in 1959. Its dwarf habit and ecology distinguish it from subsp. tripartita.