Petrophytum caespitosum
Mat rockspirea
(c) Roberto Daniel Avila, some rights reserved (CC BY) · licence
Family: Rosaceae · Type: Subshrub · Native
Petrophytum caespitosum (Mat rockspirea) is a native California subshrub in the Rosaceae family, recognized by 1 sympatric subspecies; geographically diagnostic for desert mountains region.
Mat rockspirea is a California native shrub found in rocky, montane habitats at elevations ranging from 1,500 to 2,500 meters. Flowering from June to August, this plant produces small white flowers in dense clusters 1 to 5 centimeters long, carried on branched peduncles 3 to 10 centimeters tall. Growing as a low, spreading mat 3 to 8 decimeters wide with multiple compact rosettes, it forms dense ground-covering clusters. Its leaves are simple, narrow, and prominently three-veined on the underside, creating a delicate textural appearance. The tiny fruits are approximately 2 millimeters long, containing one to two smooth, brown seeds.
Identification and appearance
Key characters: 1 sympatric subspecies; geographically diagnostic for desert mountains region
Habitat and range
California counties: Inyo, San Bernardino, Mono, Fresno, Tulare
Frequently asked questions
Is Petrophytum caespitosum native to California?
Yes. Petrophytum caespitosum is native to California (recorded as native).
Where in California does Petrophytum caespitosum grow?
Petrophytum caespitosum occurs in Inyo, San Bernardino, Mono, Fresno, Tulare.
What plant family does Petrophytum caespitosum belong to?
Petrophytum caespitosum is in the Rosaceae family, genus Petrophytum.
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.