Sisyrinchium amethystinum E. P. Bicknell; S. demissum var. amethystinum (E. P. Bicknell) Kearney & Peebles; S. longipedunculatum E. P. Bicknell

Herbs, perennial, cespitose, light green to olive when dry, to 5 dm, often somewhat glaucous. Stems branched, with 1 or 2 nodes, 1–2(–2.3) mm wide, glabrous, margins entire to denticulate apically, occasionally white-cartilaginous; first internode 8–34 cm, usually longer than leaves; distalmost node with 2–3 branches. Leaf blades glabrous, bases not persistent in fibrous tufts. Inflorescences borne singly; spathes green, obviously wider than supporting branch, glabrous, keels entire to denticulate; outer 11–26 mm, 2.5 mm shorter to 5 mm longer than inner, tapering evenly towards apex, margins basally connate 3.3–8 mm; inner with keel evenly curved to straight, hyaline margins 0.2–0.4 mm wide, apex acute to acuminate, ending 0.1–1.1 mm proximal to green apex. Flowers: tepals dark bluish violet, bases yellow; outer tepals 6–15 mm, apex rounded to acute or occasionally emarginate, aristate; filaments connate ± entirely, stipitate-glandular basally; ovary similar in color to foliage. Capsules beige to tan, globose, 4–7.5+ mm; pedicel erect to ascending. Seeds globose to obconic, lacking obvious depression, 0.8–2 mm, granular or slightly rugulose. 2n = 32, 64.

Flowering mid spring--early fall. Moist areas, springs, stream banks, meadows, forest seeps; 500--2900 m; Ariz., Colo., Nev., N.Mex., Tex., Utah; n Mexico.

Previously, we (A. F. Cholewa and D. M. Henderson 1984) misidentified the octoploid northern Utah populations of Sisyrinchium demissum as S. radicatum. New data indicate that these northern Utah populations rightly belong here as a polyploid race of S. demissum. Also see discussion under 18. S. radicatum.