Mentzelia hirsutissima
Hairy stickleaf, Hairy Stickleaf
Photo by Chez Brungraber
Family: Loasaceae · Type: Herb · Native
Conservation status: CNPS 2B.3
Mentzelia hirsutissima (Hairy stickleaf) is a native California herb in the Loasaceae family, recognized by distinctive orange petals with pointed tips and specialized stamens.
Hairy stickleaf is a rare (CNPS 2B.3) California native annual found in western Colorado Desert bioregion in creosote-bush scrub washes, fans, and slopes at elevations below 720 meters. Flowering from April to May, this plant produces pale yellow to orange flowers with obovate petals 12 to 31 millimeters long, creating delicate blooms. Growing 5 to 31 centimeters tall with erect, hairy stems that branch at the base, it develops a distinctive branching structure. Its leaves range 1 to 11 centimeters long, lanceolate to oblanceolate, with toothed or lobed edges and lower leaves that clasp the stem. The plant produces cylindrical fruits 13 to 25 millimeters long, bearing ashy-white seeds with a distinctive beak.
Identification and appearance
Key characters: 10 sympatric species; distinctive orange petals with pointed tips and specialized stamens
Habitat and range
Habitat: Washes, fans, slopes, creosote-bush scrub
Elevation: < 720 m
Outside California: Baja California
Bloom period
Mentzelia hirsutissima blooms Apr-May.
Conservation status
CNPS 2B.3
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 hirsutissima native to California?
Yes. Mentzelia hirsutissima is native to California (recorded as native).
When does Mentzelia hirsutissima bloom?
Mentzelia hirsutissima blooms Apr-May.
What plant family does Mentzelia hirsutissima belong to?
Mentzelia hirsutissima is in the Loasaceae family, genus Mentzelia.
Is Mentzelia hirsutissima rare or endangered?
Mentzelia hirsutissima carries California Rare Plant Rank 2B.3, state rank S3.
What habitat does Mentzelia hirsutissima grow in?
Mentzelia hirsutissima grows in Washes, fans, slopes, creosote-bush scrub.
Related species
Other California species in the same genus, family, or bioregion.
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.