Taxon Report

Petrophytum caespitosum (Nutt.) Rydb. ssp. acuminatum (Rydb.) Munz

marble rockmat

Print Report

Taxon Summary

Petrophytum caespitosum ssp. acuminatum, commonly known as marble rockmat, is a perennial evergreen shrub in the Rosaceae that is found only in California. It occurs within Lower montane coniferous forest, and Upper montane coniferous forest, growing at elevations from 1015 to 2300 meters. Petrophytum caespitosum ssp. acuminatum is ranked 1B.3, Plants Rare, Threatened or Endangered in California and Elsewhere; Not very threatened in California.

Classification


Scientific Name:	Petrophytum caespitosum (Nutt.) Rydb. ssp. acuminatum (Rydb.) Munz
Common Name:	marble rockmat
Family:	Rosaceae
Element Code:	PDROS18010
USDA Plants Symbol:
Synonyms/Other Names:	Petrophyton caespitosum ssp. acuminatum

Ecology and Life History


Lifeform:	perennial evergreen shrub
Blooming Period: Aug-Sep	Aug-Sep
Elevation:	1015-2300 (3330-7545)
General Habitats:	Lower montane coniferous forest, Upper montane coniferous forest
Microhabitat:	Carbonate (sometimes), Granitic (sometimes), Rocky
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.3
Global Rank:	G5T2
State Rank:	S2
State List:	None
Fed List:	None
Other Status:	SB_CalBG/RSABG; USFS_S
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	8
Element Occurrence Ranks:
Excellent (A)	1
Good (B)	1
Fair (C)	0
Poor (D)	1
None (X)	0
Unknown (U)	5

Location


California Endemic: True
California Counties and Islands: Name (Code)
Fresno (FRE), Inyo (INY), Tulare (TUL)
Quads: Name (Quad Code)
Chagoopa Falls (3611844), Coyote Flat (3711824), Mineral King (3611845), Mt. Kaweah (3611854), Mt. Williamson (3611863), North Palisade (3711815), The Sphinx (3611875), Triple Divide Peak (3611855), Wren Peak (3611877)

Threat List Data from the CNDDB


Threat List Total:	1
EOs with Threat Listed:	Total EOs	% of EOs
	1	13 %
Other	1	12%

Notes



See North American Flora 22(3):253 (1908) for original description, and Aliso 4:92 (1958) for revised nomenclature.
Threats:

Taxonomy:

Selected References

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 1 November 2025].