Leafl. W. Bot. 2: 109. 1938.
Bulbs usually solitary, not clustered on stout, primary rhizome, ovoid to ± globose, 0.9–1.7 × 0.8–2 cm; outer coats enclosing bulb, dark reddish brown, membranous, lacking cellular reticulation or cells arranged in only 2–3 rows distal to roots, ± quadrate, without fibers; inner coats light brown to white, cells obscure, quadrate. Leaves persistent, withering from tip by anthesis, 1, basally sheathing, sheath not extending much above soil surface; blade solid, terete, 20–55 cm × 1–4 mm. Scape persistent, solitary, erect, solid, terete, 15–60 cm × 1–3.5 mm. Umbel persistent, erect, compact, 15–100-flowered, hemispheric, bulbils unknown; spathe bracts persistent, 2–4, 5–8-veined, lanceolate to broadly ovate, ± equal, apex mucronate to acuminate or long-acuminate. Flowers stellate to ± campanulate, 5–8 mm; tepals spreading to ± erect, white to pink or pale lavender with darker midveins, ovate to oblong, ± equal, becoming papery in fruit, margins entire, apex obtuse; stamens ± equaling tepals to long-exserted; anthers yellow or purple; pollen yellow; ovary crested; processes 6, prominent, ± triangular, margins ± irregularly denticulate to laciniate; style linear, equaling stamens or longer; stigma capitate, 3-lobed, lobes slender, recurved; pedicel 6–25 mm. Seed coat dull or shining; cells minutely roughened.
Varieties 3 (3 in the flora).
|1||Scape 15–25(–35) cm; umbels generally 15–30 (–50)-flowered; tepals usually white to pink or lavender; ovary crests purple in fresh specimens.||Allium howellii var. howellii|
|1||Scape 20–60 cm; umbels generally 25–100-flowered; tepals usually white or pale pink; ovary crests white or greenish in fresh specimens.||> 2|
|2||Stamens exserted, 2–4 mm.||Allium howellii var. sanbenitense|
|2||Stamens ± equaling tepals.||Allium howellii var. clokeyi|