Allium dichlamydeum
Coast onion
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Family: Alliaceae · Type: Herb · Native
Allium dichlamydeum (Coast onion) is a native California herb in the Alliaceae family, recognized by coastal cliff habitat and multiple long leaves.
Coast onion is a California native perennial found in northern Coast Ranges and northern central Coast Ranges on or near sea cliffs at elevations of 50 to 150 meters. Flowering from May to July, this plant produces deep red-purple flowers in clusters of 5 to 30 blooms, each approximately 9 to 12 millimeters long. Growing with stout stems 10 to 30 centimeters tall, it emerges from a small ovoid bulb with distinctive herringbone-patterned outer layers. Its leaves are 3 to 6 in number, longer than the stem and channeled or nearly cylindrical in shape. The plant features unique ovate perianth parts with entire or dentate inner segments.
Identification and appearance
Key characters: 19 sympatric species - distinguished by coastal cliff habitat and multiple long leaves
Habitat and range
Habitat: dry clays on or near sea cliffs
Elevation: 50-150 m
California counties: Mendocino, San Francisco, Sonoma, San Mateo, Santa Clara, Marin, Mariposa, San Benito, Santa Barbara
Bloom period
Allium dichlamydeum blooms May-Jul.
How to tell it apart
vs Triteleia: Allium smells like onion when crushed; triplet lily has no smell.; vs Agapanthus: Allium smells like onion; lily-of-the-Nile has no smell and much larger flowers.; vs Dipterostemon: Allium smells like onion when crushed; ookow has no onion smell.; vs Nothoscordum: Allium smells like onion when crushed; false garlic has no smell.; vs Tulbaghia: Allium has flowers in tight umbels; society garlic has flowers in loose open clusters.
Frequently asked questions
Is Allium dichlamydeum native to California?
Yes. Allium dichlamydeum is native to California (recorded as native).
When does Allium dichlamydeum bloom?
Allium dichlamydeum blooms May-Jul.
Where in California does Allium dichlamydeum grow?
Allium dichlamydeum occurs in Mendocino, San Francisco, Sonoma, San Mateo, Santa Clara, Marin, Mariposa, San Benito and other counties, at elevations of 50-150 m.
What plant family does Allium dichlamydeum belong to?
Allium dichlamydeum is in the Alliaceae family, genus Allium.
What habitat does Allium dichlamydeum grow in?
Allium dichlamydeum grows in dry clays on or near sea cliffs.
Related species
Other California species in the same genus, family, or bioregion.
Sources: Jepson eFlora · Index of California Plant Names · CalPhotos
Last updated 2026-10-07
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.