Delphinium variegatum subsp. thornei
Thorne's royal larkspur, Thorne's Royal Larkspur
Photo: parent species Delphinium variegatum · (c) Ryan Donnelly, some rights reserved (CC BY) · licence
Family: Ranunculaceae · Type: Herb · Native
Conservation status: CNPS 1B.1
Delphinium variegatum subsp. thornei (Thorne's royal larkspur) is a native California herb in the Ranunculaceae family, recognized by sepal color and size from subsp. kinkiense.
Thorne's royal larkspur is a rare (CNPS 1B.1) California native perennial found on San Clemente Island in grassland and oak woodland habitats on slopes of 15 to 35 degrees at elevations below 500 meters. Flowering from February to May, this plant produces bright blue flowers with lateral sepals 17 to 21 millimeters long and distinctive lower petal blades 6 to 11 millimeters in size. Growing with an inflorescence featuring fewer than 12 flowers on its main axis, it develops an upright structural form characteristic of larkspur species. Its flowers showcase a vivid blue coloration, with sepals and petals creating a striking visual display against the plant's underlying vegetation. The species is notable for its limited distribution on San Clemente Island, making it a unique and localized member of California's native flora.
Identification and appearance
Key characters: 6 sympatric species; distinguished by sepal color and size from subsp. kinkiense
Habitat and range
Habitat: Grassland, oak woodland, 15--35° slopes
Elevation: < 500 m
Bloom period
Delphinium variegatum subsp. thornei blooms Feb-May.
Conservation status
CNPS 1B.1
How to tell it apart
vs Lupinus: Delphinium has backward-pointing spurs on flowers; Lupinus has pea-family flowers with banner-wing-keel structure.; vs Geranium: Delphinium has spurred bilateral flowers; Geranium has radially symmetric 5-petaled flowers with no spur.; vs Epilobium: Delphinium has spurred flowers and palmately divided leaves; Epilobium has unspurred 4-petaled flowers and simple or opposite leaves.; vs Aquilegia: Delphinium has a single spur per flower; Aquilegia has 5 spurs radiating from the center.; vs Aconitum: Delphinium has an open spur with visible stamens; Aconitum has a closed hood hiding the stamens.
Frequently asked questions
Is Delphinium variegatum subsp. thornei native to California?
Yes. Delphinium variegatum subsp. thornei is native to California (recorded as native).
When does Delphinium variegatum subsp. thornei bloom?
Delphinium variegatum subsp. thornei blooms Feb-May.
What plant family does Delphinium variegatum subsp. thornei belong to?
Delphinium variegatum subsp. thornei is in the Ranunculaceae family, genus Delphinium.
Is Delphinium variegatum subsp. thornei rare or endangered?
Delphinium variegatum subsp. thornei carries California Rare Plant Rank 1B.1, state rank S1.
What habitat does Delphinium variegatum subsp. thornei grow in?
Delphinium variegatum subsp. thornei grows in Grassland, oak woodland, 15--35° slopes.
Related species
Other California species in the same genus, family, or bioregion.
- Delphinium variegatum subsp. variegatum
- Delphinium ajacis — Doubtful knight's spur
- Delphinium andersonii — Anderson's larkspur
- Delphinium antoninum — Anthony peak larkspur
- Delphinium bakeri — Baker's larkspur
- Delphinium californicum — California larkspur
- Enemion occidentale — Western rue-anemone
- Enemion sp. — False rue-anemone
- Enemion stipitatum — Siskiyou rue-anemone
Sources: Jepson eFlora · CalPhotos · CDFW CNDDB
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.