Petrophytum caespitosum subsp. acuminatum
marble rockmat
Photo: parent species Petrophytum caespitosum · (c) Roberto Daniel Avila, some rights reserved (CC BY) · licence
Family: Rosaceae · Type: Shrub · Native
Conservation status: CNPS 1B.3
Petrophytum caespitosum subsp. acuminatum (marble rockmat) is a native California shrub in the Rosaceae family, recognized by endemic to southern Sierra Nevada limestone habitats.
Marble rockmat is a rare (CNPS 1B.3) California native shrub found in southern Sierra Nevada Mountains on limestone cliffs and in conifer forests at elevations of 900 to 2,350 meters. Flowering from June to September, this plant produces white to cream-colored flowers in dense, compact clusters. Growing with low-spreading, compact stems that form tight mats or cushions, it creates intricate ground-hugging formations. Its small leaves are densely clustered, overlapping, and arranged in tight rosettes, giving the plant a distinctive cushion-like appearance. The fruit is a small capsule characteristic of its rocky, high-elevation habitat.
Identification and appearance
Key characters: Geographically isolated; endemic to southern Sierra Nevada limestone habitats
Habitat and range
Habitat: Limestone cliffs, conifer forest
Elevation: 900-2350 m
California counties: Fresno, San Bernardino
Bloom period
Petrophytum caespitosum subsp. acuminatum blooms Jun-Sep.
Conservation status
CNPS 1B.3
Frequently asked questions
Is Petrophytum caespitosum subsp. acuminatum native to California?
Yes. Petrophytum caespitosum subsp. acuminatum is native to California (recorded as native).
When does Petrophytum caespitosum subsp. acuminatum bloom?
Petrophytum caespitosum subsp. acuminatum blooms Jun-Sep.
Where in California does Petrophytum caespitosum subsp. acuminatum grow?
Petrophytum caespitosum subsp. acuminatum occurs in Fresno, San Bernardino, at elevations of 900-2350 m.
What plant family does Petrophytum caespitosum subsp. acuminatum belong to?
Petrophytum caespitosum subsp. acuminatum is in the Rosaceae family, genus Petrophytum.
Is Petrophytum caespitosum subsp. acuminatum rare or endangered?
Petrophytum caespitosum subsp. acuminatum carries California Rare Plant Rank 1B.3, state rank S2.
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 2026-10-06
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.