Twincrest Onion

Two varieties of Allium bisceptrum have been recognized. Where their ranges overlap (central Utah and central Nevada), the putative varieties cannot be distinguished confidently except by chromosome number.

Bulbs 1–7+, commonly producing either cluster of stalked, basal bulbels or filiform rhizomes to 1 dm, terminated by bulbels, rhizomes generally lost when specimens are collected, ovoid, 1–2 × 0.6–1.8 cm; outer coats enclosing 1 or more bulbs, light brown to gray, membranous, obscurely cellular-reticulate, cells rectangular, walls minutely sinuous, vertical, varying to irregular, all sinuous, without fibers; inner coats white to pink, cells obscure, quadrate. Leaves persistent, green at anthesis, 2–5, basally sheathing, sheaths not extending much above soil surface; blade solid, flat, broadly channeled, 8–30 cm × 1–13 mm, margins entire. Scape persistent, solitary or clustered 1–3, erect, solid, terete, 10–30(–40) cm × 1–5 mm. Umbel persistent, erect, loose, 15–40-flowered, globose, bulbils unknown; spathe bracts persistent, 2, 3–4-veined, ovate to lanceolate, ± equal, apex acuminate. Flowers stellate, 7–10 mm; tepals spreading, lilac to white, lanceolate, ± equal, becoming papery in fruit, not carinate, margins entire, apex acuminate, not involute; stamens included; anthers purple; pollen yellow; ovary conspicuously crested; processes 6, central, distinct, flattened, triangular, margins papillose-denticulate; style included, linear, ± equaling stamens; stigma capitate, unlobed; pedicel 10–20 mm, often becoming flexuous and deflexed in fruit. Seed coat shining; cells each with minute, central papilla. 2n = 14, 28.

Ariz., Calif., Idaho, Nev., N.Mex., Oreg., Utah.

Flowering May--Jul.

Meadows and aspen groves, less commonly on open slopes in mountains; 1100--3000m.

Allium bisceptrum var. palmeri (S. Watson) A. Cronquist; A. bisceptrum var. utahense M. E. Jones; A. palmeri S. Watson