Bulbs 1-12+, not basally clustered on stout primary rhizome, ovoid, 2-3 × 1.5-2 cm; outer coats enclosing 1 or more bulbs, brown, membranous, lacking cellular reticulation or cells arranged in only 2-3 rows distal to roots, ± quadrate, without fibers; inner coats white, cells very obscurely quadrate or not visible. Leaves usually deciduous with scape, withering from tip at anthesis, 2, basally sheathing, sheaths not extending much above soil surface; blade solid, flat or very broadly channeled, ± falcate, 15-40 cm × 2-18 mm, margins entire. Scape usually forming abcission layer and deciduous with leaves after seeds mature, frequently breaking at this level after pressing, solitary, erect, solid, terete, 6-23 cm × 1-3 mm. Umbel persistent, erect, compact, 20-100-flowered, globose to hemispheric, bulbils unknown; spathe bracts persistent, 2-4, 7-9-veined, ovate, ± equal, apex acuminate. Flowers campanulate, 7-15 mm; tepals erect, white to pink with darker midveins, linear-oblong, ± equal, becoming membranous in fruit, margins entire, apex acute; stamens ± equaling tepals; anthers yellow or purple; pollen yellow; ovary crested; processes 3, 2-lobed, minute, margins entire; style short-exserted, linear; stigma capitate, scarcely thickened, unlobed; pedicel 7-34 mm. Seed coat dull; cells ± smooth. 2n = 14.

Flowering May--Jun. Moist soil along cracks and margins of large metamorphic outcrops; of conservation concern; 800--2200 m; Calif.

Allium yosemitense is known only from the central Sierra Nevada.