Taxon Report

Aphyllon validum (Jeps.) A.C. Schneid. ssp. howellii (Heckard & L.T. Collins) A.C. Schneid.

Howell's broomrape

Print Report

Taxon Summary

Aphyllon validum ssp. howellii, commonly known as Howell's broomrape, is a perennial herb (parasitic) in the Orobanchaceae that is found only in California. It occurs within Chaparral (serpentinite, and volcanic), growing at elevations from 180 to 1740 meters. Aphyllon validum ssp. howellii is ranked 4.3, Plants of Limited Distribution, A Watch List; Not very threatened in California.

Classification


Scientific Name:	Aphyllon validum (Jeps.) A.C. Schneid. ssp. howellii (Heckard & L.T. Collins) A.C. Schneid.
Common Name:	Howell's broomrape
Family:	Orobanchaceae
Element Code:	PDORO040G1
USDA Plants Symbol:	ORVAH
Synonyms/Other Names:	Orobanche valida ssp. howellii

Ecology and Life History


Lifeform:	perennial herb (parasitic)
Blooming Period: Jun-Sep	Jun-Sep
Elevation:	180-1740 (590-5710)
General Habitats:	Chaparral
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	4.3
Global Rank:	G4T3
State Rank:	S3
State List:	None
Fed List:	None
Other Status:
CRPR Changes:

Occurrence Data from the CNDDB


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

Location


California Endemic: True
California Counties and Islands: Name (Code)
Glenn (GLE), Lake (LAK), Mendocino (MEN), Napa (NAP), Sonoma (SON), Tehama (TEH)
Quads: Name (Quad Code)
Chiles Valley (3812253), Chrome (3912265), Detert Reservoir (3812265), Fouts Springs (3912236), Hough Springs (3912225), Jericho Valley (3812274), Knoxville (3812273), Mount St. Helena (3812266), Potato Hill (3912237), Riley Ridge (3912286), Sanhedrin Mtn. (3912351), The Geysers (3812277), Whispering Pines (3812276), Wilbur Springs (3912214)

Threat List Data from the CNDDB


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

Notes



Generally parasitic on Garrya spp. See Madroño 29(2):95-100 (1982) for original description.
Threats:

Taxonomy:

Selected References

Non-Substantive Name Changes: Orobanche to Aphyllon (2023)

Phytokeys 75: 10-118 (2016)

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 14 June 2025].