Rawhide H Ill Onion

Allium tuolumnense is known only from the foothills of the central Sierra Nevada, Rawhide Hill and Red Hills.

Bulbs usually solitary, not clustered on stout, primary rhizomes, ovoid, 1.3–2 × 1.4–2 cm; outer coats enclosing single 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, cells obscure, quadrate. Leaves persistent, withering from tip by anthesis, 1, basally sheathing, sheath not extending much above soil surface; blade solid, terete, 30–55 cm × 2–4 mm. Scape persistent, solitary, erect, solid, terete, 25–50 cm × 2–4 mm. Umbel persistent, erect, compact, 20–60-flowered, hemispheric, bulbils unknown; spathe bracts persistent, usually 3, 7–8-veined, ovate, ± equal, apex attenuate. Flowers saucer-shaped, 6–8 mm; tepals spreading from base, white or flushed with pink, broadly ovate, ± equal, becoming papery in fruit, margins entire, apex obtuse to nearly round, not recurved at tip; stamens included; anthers yellow; pollen yellow; ovary crested; processes 6, prominent, ± triangular, margins laciniate; style linear, equaling stamens; stigma capitate, 3-lobed, lobes slender, recurved; pedicel 7–20 mm. Seed coat dull; cells minutely roughened. 2n = 14.

Calif.

Flowering Mar--May.

Serpentine soil on open hillsides; of conservation concern; 400--600m.

Allium sanbornii Alph. Wood var. tuolumnense Ownbey & Aase ex Traub, Pl. Life 28: 63. 1972

Allium tuolumnense is a rare species of wild onion, known by the common name Rawhide Hill onion.

It is endemic to Tuolumne County, California, where it is known only from a small section of the Sierra Nevada foothills at Rawhide Hill and the Red Hills. It is a plant of serpentine soils.