Taxon Report

Horkelia cuneata Lindl. var. puberula (Rydb.) Ertter & Reveal

mesa horkelia

Print Report

© 2008 Tony Morosco

Taxon Summary

Horkelia cuneata var. puberula, commonly known as mesa horkelia, is a perennial herb in the Rosaceae that is found only in California. It occurs within Chaparral (maritime), Cismontane woodland, and Coastal scrub, growing at elevations from 70 to 810 meters. Horkelia cuneata var. puberula is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.

Classification


Scientific Name:	Horkelia cuneata Lindl. var. puberula (Rydb.) Ertter & Reveal
Common Name:	mesa horkelia
Family:	Rosaceae
Element Code:	PDROS0W045
USDA Plants Symbol:
Synonyms/Other Names:	Horkelia cuneata ssp. puberula

Ecology and Life History


Lifeform:	perennial herb
Blooming Period: Feb-Jul(Sep)	Feb-Jul(Sep)
Elevation:	70-810 (230-2660)
General Habitats:	Chaparral, Cismontane woodland, Coastal scrub
Microhabitat:	Gravelly (sometimes), Sandy (sometimes)
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.1
Global Rank:	G4T1
State Rank:	S1
State List:	None
Fed List:	None
Other Status:	BLM_S; SB_CalBG/RSABG; USFS_S
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	103
Element Occurrence Ranks:
Excellent (A)	0
Good (B)	4
Fair (C)	2
Poor (D)	1
None (X)	24
Unknown (U)	72

Location


California Endemic: True
California Counties and Islands: Name (Code)
Los Angeles (LAX), Orange (ORA), Riverside (RIV), San Bernardino (SBD), San Diego (SDG), San Luis Obispo (SLO), Santa Barbara (SBA), Ventura (VEN)
Quads: Name (Quad Code)
Alberhill (3311764), Arroyo Grande NE (3512025), Atascadero (3512046), Azusa (3411728), Baldwin Park (3411718), Beaumont (3311688), Beverly Hills (3411814), Black Star Canyon (3311776), Burbank (3411823), Cabazon (3311687), Calabasas (3411826), Cambria (3512151), Canada Gobernadora (3311755), Casmalia (3412075), Cucamonga Peak (3411725), Cypress Mountain (3512058), Devore (3411724), Dos Pueblos Canyon (3411948), El Monte (3411811), Fontana (3411714), Gaviota (3412042), Glendora (3411727), Goleta (3411947), Guasti (3411715), Hollywood (3411813), Laguna Beach (3311757), Little Pine Mtn. (3411956), Lompoc (3412064), Lompoc Hills (3412054), Los Alamos (3412063), Los Angeles (3411812), Manzanita Mtn. (3412081), Matilija (3411943), Miranda Pine Mtn. (3512011), Morro Bay South (3512037), Mt. Wilson (3411821), Nipomo (3512014), Oceano (3512015), Ontario (3411716), Orcutt (3412074), Pala (3311731), Pasadena (3411822), Pechanga (3311741), Pismo Beach (3512026), Pitas Point (3411934), Point Dume (3411817), Port San Luis (3512027), Redondo Beach (3311874), Sacate (3412043), San Bernardino South (3411713), San Dimas (3411717), San Fernando (3411834), San Luis Obispo (3512036), San Marcos Pass (3411957), Santa Barbara (3411946), Santa Rosa Hills (3412053), Simi (3411837), Sisquoc (3412073), Sitton Peak (3311754), Solvang (3412052), Surf (3412065), Tar Spring Ridge (3512024), Templeton (3512056)*, Tranquillon Mtn. (3412055), Triunfo Pass (3411818), Twitchell Dam (3412083), Van Nuys (3411824), Venice (3311884), Waterman Mtn. (3411738), Wheeler Springs (3411953), White Ledge Peak (3411944), Zaca Creek (3412062)

Threat List Data from the CNDDB


Threat List Total:	7
EOs with Threat Listed:	Total EOs	% of EOs
	45	44 %
Development	41	39%
Road/trail construction/maint.	3	2%
Wood cutting or brush clearing	2	1%
Mining	2	1%
Non-native plant impacts	1	0%
Other	1	0%
Landfill	1	0%

Notes



Many historical occurrences extirpated; need current information on status of occurrences. Possibly threatened by habitat conversion. Intergrades with other sspp.; populations representing true ssp. puberula declining. See Pittonia 1:102 (1887) for original description, and Lloydia 1:87-88 (1938) and Novon 17(3):315-325 (2007) for revised nomenclature.
Threats:
Possibly threatened by habitat conversion.
Taxonomy:
ntergrades with other sspp.; populations representing true ssp. puberula declining.

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 9 May 2025].