Common Yampah, Gairdner's Yampah, Gardner's Yampah, Squawroot, Western False Caraway: Perideridia gairdneri ssp. borealis (Synonym: Perideridia montana) - Petioles and base of scape less than 2 mm thick at the base. Main leaves once divided or partially twice pinnately or ternately divided into narrow segments of relatively equal length and less than 2 mm wide. Petals 5- or 7-veined. Fruits spherical or nearly so, 2-3.5 mm in diameter.
Eppaw, Oregon Yampah, Squaw-potato: Perideridia oregana (Synonyms: Atenia oregana, Carum oregana) - Petioles and base of scape less than 2 mm thick at the base. Main leaves once divided or partially twice pinnately or ternately divided into narrow segments of relatively equal length and less than 2 mm wide. Only west of the Cascade?