Bulbs 2-10+, forming threadlike rhizomes, rhizomes 3-10 cm, terminated by bulbels and/or 1-2 basal bulbels that in turn may produce threadlike rhizomes, ± globose, 1-1.5 × 1-1.5 cm; outer coats enclosing single bulb, brown, membranous, lacking cellular reticulation or cells arranged in only 2-3 rows distal to roots, ± quadrate, without fibers; inner coats light yellow, turning reddish on drying, cells obscure, ± quadrate. Leaves persistent, withering from tip by anthesis, 1, basally sheathing, sheath not extending much above soil surface; blade solid, terete, 20-40 cm × 2-4 mm. Scape persistent, solitary, erect, solid, terete, 10-20+ cm × 1-5 mm. Umbel persistent, erect, compact, 12-30-flowered, globose, bulbils unknown; spathe bracts persistent, usually 3, 5-7-veined, lanceolate, ± equal, apex apiculate. Flowers campanulate, 12-14 mm; tepals spreading, unequal; outer tepals maroon, oblanceolate, margins irregularly shallow-toothed, apex acute to mucronate, reflexed-curled; inner tepals maroon distally, white proximally, ovate, withering in fruit, curled back at tip, margins entire, apex acute, reflexed; stamens included; anthers yellow; pollen yellow; ovary crested; processes 6, prominent, narrowly triangular, margins entire, apex emarginate; style linear, equaling stamens; stigma capitate, 3-lobed, lobes slender, recurved; pedicel 10-16 mm. Seed coat shining; cells minutely roughened. 2n = 14.

Flowering Jun--Jul. Soil pockets on schist outcrops; of conservation concern; 2200--2400 m; Calif.

Allium shevockii is known only from the upper slopes of Spanish Needle Peak in the southern Sierra Nevada and from Horse Canyon, Tehachapi Mountains.