Taxon Report

Castilleja ambigua Hook. & Arn. var. heckardii J. M. Egger & Excoffier

Heckard's owl's-clover

Print Report

Taxon Summary

Castilleja ambigua var. heckardii, commonly known as Heckard's owl's-clover, is a annual herb in the Orobanchaceae that is . It occurs within Coastal prairie, growing at elevations from 50 to 180 meters. Castilleja ambigua var. heckardii is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.

Classification


Scientific Name:	Castilleja ambigua Hook. & Arn. var. heckardii J. M. Egger & Excoffier
Common Name:	Heckard's owl's-clover
Family:	Orobanchaceae
Element Code:	PDSCR0D405
USDA Plants Symbol:
Synonyms/Other Names:

Ecology and Life History


Lifeform:	annual herb
Blooming Period: May-Jul	May-Jul
Elevation:	50-180 (165-590)
General Habitats:	Coastal prairie
Microhabitat:	Openings, Sandy, Vernally Mesic
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.1
Global Rank:	G5T1
State Rank:	S1
State List:	None
Fed List:	None
Other Status:
CRPR Changes:	added to 1B.1 on 2022-04-07

Occurrence Data from the CNDDB


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

Location


California Endemic: False
California Counties and Islands: Name (Code)
San Luis Obispo (SLO)
Quads: Name (Quad Code)
Burro Mountain (3512173), Piedras Blancas (3512163)

Threat List Data from the CNDDB


Threat List Total:	0
EOs with Threat Listed:	Total EOs	% of EOs
	0	%

Notes




Threats:
Potentially threatened by inappropriate grazing and non-native plants.
Taxonomy:
Previously identified as C. ambigua ssp. ambigua and ssp. insalutata.

Selected References

Proposed Addition to CRPR 1B.1, G5T1 / S1 (2022)

Phytoneuron 15: 1–17 (2021)

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].