Bulbs 1–3, increase bulbs absent and ± equaling parent bulbs, never appearing as basal cluster, not clustered on stout primary rhizome, ovoid to ± globose, 0.8–1.2 × 0.8–1.2 cm; outer coats enclosing 1 or more bulbs, brown, prominently cellular-reticulate, membranous, cells arranged in ± vertical rows, forming distinct herringbone pattern, transversely elongate, V-shaped, without fibers; inner coats white, cells obscure, arranged in vertical rows, forming distinct herringbone pattern or ± quadrate, V-shaped. Leaves persistent, withering from tips at anthesis, 2–3, basally sheathing, sheaths not extending much above soil surface; blade solid, subterete, channeled, 13–35 cm × 1–4 mm, margins entire. Scape persistent, solitary, erect, solid, terete, 1.5–4 cm × 2–3 mm. Umbel shattering after seeds mature, each flower deciduous with its pedicel as a unit, erect, compact, 10–40-flowered, hemispheric to globose, bulbils unknown; spathe bracts persistent, 2–3, 5–6-veined, lance-ovate to ovate, ± equal, apex acuminate. Flowers urceolate to campanulate, 8–11 mm; tepals erect, pink, lanceolate to lance-ovate, unequal, inner shorter and narrower than outer, becoming papery and connivent over capsule, margins entire, apex acute; stamens included; anthers yellow; pollen yellow; ovary crested; processes 3, central, 2-lobed, minute, margins entire; style linear, equaling stamens; stigma capitate, scarcely thickened, 3-lobed; pedicel 7–15 mm. Seed coat dull; cells minutely roughened. 2n = 14.
Phenology: Flowering Apr–May.
Habitat: Heavy, clay soils, including serpentine
Elevation: 30–1200 m
Allium serra is known only from the central and north Coast Ranges.