Bulbs 2–4, terminating thick, iris-like rhizome, elongate, 2–3 × 0.6–1 cm; outer coats enclosing single bulb, grayish or brownish, membranous, minutely striate, cells in parallel vertical rows, narrow, elongate, not fibrous-reticulate, fibers persistent, parallel, few, coarse; inner coats whitish, cells narrowly vertically elongate. Leaves persistent, green at anthesis, 2–5, basally sheathing, sheaths not extending much above soil level; blade solid, flat, 10–40 cm × 2–8 mm, margins entire. Scape persistent, solitary, erect, solid, flattened and narrowly winged distally, 20–60 cm × 1.5–4 mm. Umbel persistent, erect, loose, 7–20-flowered, subhemispheric, bulbils unknown; spathe bracts persistent, 2, 3–5-veined, ovate, ± equal, apex acute. Flowers narrowly urceolate, 10–13 mm; tepals erect, pink, lanceolate, ± equal, withering in fruit, margins entire, apex acuminate, midribs somewhat thickened; stamens included, ca. 1/2 as long as tepals; anthers yellow; pollen light yellow; ovary crestless; style linear, equaling stamens; stigma capitate, distinctly 3-lobed; pedicel 8–35 mm, elongating and becoming stout and curved in fruit. Seed coat dull or shining; cells each with minute, central papilla, or obscurely and minutely roughened. 2n = 14.
Phenology: Flowering Jun–Aug.
Habitat: Swampy meadows and along streams, rarely on wooded slopes
Elevation: 2200–3400 m
Colo., Idaho, Mont., N.Mex., Utah, Wyo.
Allium brevistylum is found only in the Rocky Mountains.