Erythronium tuolumnense aka Tuolumne Fawn Lily

Erythronium tuolumnense is a bulbous perennial in the lily family. Common names include Tuolumne fawn lily and dog's tooth violet. It comes from Tuolumne County in central California. Its native range lies within a temperate climate. PFAF describes it as very rare in the wild. It grows in chaparral, pine woods, and foothill woodland. These sites lie at 984–1,969 feet [300–600 metres] above sea level.

The plant forms clumps and loses its leaves each year. Its green leaves have a slight sheen and wavy edges. Chicago Botanic Garden describes its growth as upright. Garden plants reach about 1 foot [0.3 metres] tall. The RHS gives a broader height range reaching 1.6 feet [0.5 metres]. Its listed spread reaches about 0.3 feet [0.1 metres]. The RHS gives two to five years to reach full size. Each stem can hold up to four yellow flowers. The blooms hang down and span about 0.13 feet [0.04 metres]. Chicago records flowering in March and April.

Grow this species in partial shade with soil that stays moist. The RHS calls for fertile soil rich in humus. Good drainage matters, but the soil should not dry out. It accepts chalk, clay, loam, and sand. It also tolerates acid, neutral, and alkaline soil. Plant bulbs about 0.33 feet [0.1 metres] deep. Keep stored bulbs slightly damp rather than letting them dry. Chicago lists USDA zones 5–8 for this species. The RHS rates its UK hardiness as H5.

Its spring flowers suit beds, borders, and woodland gardens. The RHS also suggests rock gardens and planting beneath shrubs. PFAF lists woodland sites with broken shade and shaded edges. Divide plants after the flowers finish to make more plants. No pruning is needed. Slugs may cause damage, though the RHS reports few disease problems. These traits support its use as a spring garden bulb.

The RHS warns against eating these ornamental bulbs. Its warning covers both people and pets. Wear gloves and protective gear when handling them. PFAF assigns an edible rating, but lacks species-specific evidence for bulb edibility. That does not establish this species as safe food. PFAF lists no known medicinal or other practical uses.