Bull. Torrey Bot. Club 26: 445. 1899.
Herbs, perennial, cespitose, green to ashy olive when dry, to 4.5 dm, not glaucous; rhizomes scarcely discernable. Stems simple, obviously winged, 1–2.5 mm wide, glabrous, margins entire to denticulate apically, similar in color and texture to stem body. Leaf blades glabrous, bases not persistent in fibrous tufts. Inflorescences borne singly; spathes usually green, glabrous, keels entire to denticulate; outer 14–55(–65) mm, 13–16 mm longer than inner, basally connate 2.6–7 mm, tapering evenly towards apex; inner with keel evenly curved to straight, hyaline margins 0.1–0.5 mm wide, apex acuminate to acute, ending 0.5–2.1 mm proximal to green apex. Flowers: tepals light to deep bluish violet or occasionally purple, bases yellow; outer tepals 8–20 mm, apex rounded, truncate, or emarginate, aristate; filaments connate ± entirely, stipitate-glandular basally; ovary similar in color to foliage. Capsules beige to light or dark brown, occasionally with purple blotches on apex, ± globose to pyriform, 3–6 mm; pedicel erect to ascending. Seeds globose to obconic, lacking obvious depression, 0.8–1.8 mm, usually granular.
w North America.
Varieties 4 (4 in the flora).
|1||Stems less than 1.5 mm wide.||> 2|
|1||Stems 1.5 mm or more wide.||> 3|
|2||Outer tepals 18–20 mm; outer spathe at least 2 times inner; margins of stem and keels of spathes entire.||Sisyrinchium idahoense var. macounii|
|2||Outer tepals 10–17 mm; outer spathe less than 2 times inner; margins of stem and keels of spathes denticulate.||Sisyrinchium idahoense var. segetum|
|3||Outer tepals 8–13 mm; inner spathe 12–20 mm; stem 1.5–2 mm wide.||Sisyrinchium idahoense var. occidentale|
|3||Outer tepals 13–17(–20) mm; inner spathe 20–30 mm; stem 2–2.5 mm wide.||Sisyrinchium idahoense var. idahoense|