Dichelostemma is a genus of perennial, corm-forming herbs native to western North America, belonging to the family Asparagaceae (order Asparagales). It is closely allied to Brodiaea and has sometimes been treated as part of that genus; earlier classifications placed it in the segregate family Themidaceae or in the broadly circumscribed Liliaceae.
Plants grow from fibrous-coated corms and produce 1-5 narrow, basal leaves with keeled and channeled blades. The scape is solitary, often slender and curved, sometimes twining in D. volubile. Inflorescences are umbellate or racemose, dense, and carry 2-20 flowers with a 6-tepaled perianth whose base is fused into a distinct tube -- cylindrical, ovoid, or campanulate. A characteristic corona of perianth appendages arises at the junction of the tube and limb lobes. Most species have 3 stamens; D. capitatum is unusual in bearing 6. Seeds are black, sharply angled, and borne in firm, 3-angled capsular fruits.
The genus is centered in northern California but ranges east to New Mexico, north to British Columbia, and south into northwestern Mexico. Corms of several species were a traditional food source for Native Americans across this range.
Well-known members include D. capitatum (blue dicks), one of the most widespread wildflowers of the California chaparral; D. ida-maia (firecracker flower), distinguished by its bright red tubular flowers; D. volubile (twining brodiaea), whose scape twists around shrubs for support; and D. congestum and D. multiflorum, common in grasslands and open woodlands.
Etymology
The name Dichelostemma derives from the Greek dichelos ("toothed" or "cleft") and stemma ("crown"), referring to the distinctive corona formed by the perianth appendages that ring the stamens inside the flower tube.
Distribution
Dichelostemma is native to western North America, with its greatest diversity in northern California. The range extends east to New Mexico, north to British Columbia in Canada, and south into northwestern Mexico. Species are common in grasslands, chaparral, oak woodlands, and mixed conifer forests at a range of elevations.
Cultural Uses
Corms of several Dichelostemma species were harvested and eaten by Indigenous peoples across the western United States. They were typically roasted or pit-cooked, and served as an important starchy food resource in regions where the plants grow abundantly.
Taxonomy Notes
Dichelostemma has a complex nomenclatural history. The earliest name published for a member of this group, Hookera pulchella Salisbury, has uncertain application and has been variously associated with D. congestum, D. capitatum, or other species. The genus has historically been included within Brodiaea and has also been treated in the segregate family Themidaceae; current APG classifications place it in Asparagaceae. The related genus Dipterostemon has also been used for some members.
