Sharsmith's Onion

Allium sharsmithiae is known only from the Mount Hamilton Range.

Bulbs usually solitary, not clustered on stout, primary rhizome, ovoid to globose, 1–1.8 × 1–1.5 cm; outer coats enclosing bulb, reddish brown, membranous, lacking cellular reticulation or cells arranged in only 2–3 rows distal to roots, ± quadrate, without fibers; inner coats pale brown, cells obscure, quadrate. Leaves persistent, withering from tip by anthesis, 1, basally sheathing, sheath not extending much above soil surface; blade solid, terete, 15–25 cm × 1–4 mm. Scape persistent, solitary, erect, solid, terete, 4–17 cm × 1–2.5 mm. Umbel persistent, erect, compact, 5–50-flowered, hemispheric, bulbils unknown; spathe bracts persistent, 2–3, 3–8-veined, lanceolate to lance-ovate, ± equal, apex long-acuminate to setaceous. Flowers urceolate, 10–18 mm; tepals erect, deep reddish purple, linear-lanceolate to lance-ovate, ± equal, becoming rigid in fruit, margins entire, apex acute to obtuse, recurved-spreading at tips; stamens included; anthers yellow; pollen yellow; ovary crested; processes 6, prominent, ± triangular, margins entire, surfaces usually papillate; style linear, equaling stamens; stigma capitate, 3-lobed, lobes slender, recurved; pedicel 6–19 mm. Seed coat dull or shining; cells minutely roughened. 2n = 14.

Calif.

Flowering Apr--May.

Serpentine clay soil on talus slopes; of conservation concern; 500--1100m.

Allium fimbriatum S. Watson var. sharsmithiae Ownbey & Aase ex Traub, Pl. Life 28: 64. 1972 (as sharsmithae)

Allium sharsmithiae, called the Mount Hamilton onion or Helen Sharsmith's onion, is a rare species of wild onion endemic to a small region in California. It is found on serpentine soils in the vicinity of Mount Hamilton, in the Diablo Range south of San Francisco Bay in Santa Clara, Alameda and Stanislaus Counties.