Petalonyx linearis
Long leaved sandpaper plant
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Family: Loasaceae · Type: Shrub · Native
Conservation status: CNPS 2B.3
Petalonyx linearis (Long leaved sandpaper plant) is a native California shrub in the Loasaceae family.
Long leaved sandpaper plant is a rare (CNPS 2B.3) California native shrub found in southeastern Mojave Desert and Sonoran Desert regions in sandy or rocky canyons, typically within creosote-bush scrub at elevations below 1,000 meters. Flowering from March to May, this plant produces white flowers with petals 2 to 5.5 millimeters long in delicate clusters. Growing 15 to 100 centimeters tall with an upright, spreading form, it develops woody stems that support its distinctive structure. Its leaves are generally linear to narrowly lance-shaped, 10 to 25 millimeters long, sessile and either entirely smooth or irregularly toothed near the tips. The plant's stamens extend slightly beyond the flower petals, creating an elegant, airy appearance in its desert habitat.
Identification and appearance
Key characters: 2 sympatric species; key differentiator is leaf shape (linear vs broader)
Habitat and range
Habitat: Sandy or rocky canyons, generally in creosote-bush scrub
Elevation: < 1000 m
California counties: Riverside, San Bernardino, Imperial, San Diego
Outside California: southwestern Arizona, northwestern Mexico
Bloom period
Petalonyx linearis blooms Mar-May.
Conservation status
CNPS 2B.3
How to tell it apart
vs Ambrosia: Petalonyx has showy white 5-petaled flowers; Ambrosia has tiny greenish flowers in heads.; vs Atriplex: Petalonyx has 5-petaled flowers; Atriplex has no petals, only sepals.; vs Eriastrum: Petalonyx has 5 stamens and woody stems; Eriastrum has many stamens and herbaceous stems.; vs Galium: Petalonyx has 5-petaled flowers; Galium has 4-petaled flowers in whorls.; vs Eucnide: Petalonyx is a woody shrub; Eucnide is an annual herb.
Frequently asked questions
Is Petalonyx linearis native to California?
Yes. Petalonyx linearis is native to California (recorded as native).
When does Petalonyx linearis bloom?
Petalonyx linearis blooms Mar-May.
Where in California does Petalonyx linearis grow?
Petalonyx linearis occurs in Riverside, San Bernardino, Imperial, San Diego, at elevations of < 1000 m.
What plant family does Petalonyx linearis belong to?
Petalonyx linearis is in the Loasaceae family, genus Petalonyx.
Is Petalonyx linearis rare or endangered?
Petalonyx linearis carries California Rare Plant Rank 2B.3, state rank S3?.
Related species
Other California species in the same genus, family, or bioregion.
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.