Mentzelia tricuspis
Spiny-hair blazing star
(c) Stan Shebs, some rights reserved (CC BY-SA) · licence
Family: Loasaceae · Type: Herb · Native
Conservation status: CNPS 2B.1
Mentzelia tricuspis (Spiny-hair blazing star) is a native California herb in the Loasaceae family.
Spiny-hair blazing star is a rare (CNPS 2B.1) California native annual found in southern Desert Mojave and southwestern Sonoran Desert regions on sandy or gravelly slopes in creosote-bush scrub at elevations of 150 to 1,280 meters. Flowering from March to May, this plant produces white to pale yellow flowers with widely obovate petals 11 to 30 millimeters long, featuring a distinctive mucronate tip. Growing 5 to 27 centimeters tall with erect stems covered in spiny hairs, it develops lanceolate to ovate leaves that are wavy or slightly toothed. Its leaves range from 2 to 12 centimeters long and are sessile or short-petioled, with a distinctive green coloration. The fruit is cylindric to barrel-shaped, standing erect or slightly reflexed and measuring 9 to 18 millimeters long.
Identification and appearance
Key characters: 15 sympatric species; seed shape and stamen structure are key differentiators
Habitat and range
Habitat: Sandy or gravelly slopes or washes in creosote-bush scrub
Elevation: 150-1280 m
California counties: San Bernardino, Kern, Riverside, Imperial, Tulare
Outside California: to Utah, Arizona
Bloom period
Mentzelia tricuspis blooms Mar-May.
Conservation status
CNPS 2B.1
How to tell it apart
vs Camissoniopsis: Mentzelia has many stamens and 3 stigmas; Camissoniopsis has 8 stamens and 4 stigmas.; vs Leptosiphon: Mentzelia has free petals and many stamens; Leptosiphon has fused petals forming a tube.; vs Emmenanthe: Mentzelia has free petals and 3 stigmas; Emmenanthe has fused bell-shaped petals.; vs Eschscholzia: Mentzelia has many stamens and 3 stigmas; Eschscholzia has many stamens and 4 stigmas.; vs Potentilla: Mentzelia has 3 stigmas and capsule fruit; Potentilla has many pistils and achene fruits.
Frequently asked questions
Is Mentzelia tricuspis native to California?
Yes. Mentzelia tricuspis is native to California (recorded as native).
When does Mentzelia tricuspis bloom?
Mentzelia tricuspis blooms Mar-May.
Where in California does Mentzelia tricuspis grow?
Mentzelia tricuspis occurs in San Bernardino, Kern, Riverside, Imperial, Tulare, at elevations of 150-1280 m.
What plant family does Mentzelia tricuspis belong to?
Mentzelia tricuspis is in the Loasaceae family, genus Mentzelia.
Is Mentzelia tricuspis rare or endangered?
Mentzelia tricuspis carries California Rare Plant Rank 2B.1, state rank S2.
Related species
Other California species in the same genus, family, or bioregion.
- Mentzelia tridentata — Creamy blazing star
- Mentzelia veatchiana — Veatch's blazing star
- Mentzelia affinis — Yellow blazing star
- Mentzelia albicaulis — Small flowered blazing star
- Mentzelia congesta — Clustered blazing star
- Mentzelia crocea — Saffron blazing star
- Petalonyx linearis — Long leaved sandpaper plant
- Petalonyx nitidus — Shiny leaf sandpaper plant
Sources: Jepson eFlora · CNPS Rare Plant Inventory · Index of California Plant Names · 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.