Petalonyx thurberi
Sandpaper plant
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Family: Loasaceae · Type: Shrub · Native
Petalonyx thurberi (Sandpaper plant) is a native California shrub in the Loasaceae family.
Sandpaper plant is a California native shrub found in desert regions, growing in arid habitats at elevations between 100 to 1,000 meters. Flowering from spring to early summer, this plant produces delicate cream-colored flowers with petals 2.5 to 6.5 millimeters long, featuring well-exserted stamens. Growing as a compact shrub less than one meter tall, it develops stiff, densely packed branches. Its leaves are distinctive, clasping the stems and ranging from 4 to 45 millimeters long, with lanceolate to deltate-ovate shapes that can be entire or slightly toothed. The plant's rough-textured foliage gives it the common name "sandpaper plant," with leaves that are acute to acuminate in appearance.
Identification and appearance
Key characters: 0 sympatric species; geographically isolated but range data incomplete
Habitat and range
California counties: San Diego, Kern, Los Angeles, Imperial, Riverside, San Bernardino, Inyo, Tulare
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 thurberi native to California?
Yes. Petalonyx thurberi is native to California (recorded as native).
Where in California does Petalonyx thurberi grow?
Petalonyx thurberi occurs in San Diego, Kern, Los Angeles, Imperial, Riverside, San Bernardino, Inyo, Tulare.
What plant family does Petalonyx thurberi belong to?
Petalonyx thurberi is in the Loasaceae family, genus Petalonyx.
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.