Taxon Report

Mentzelia ravenii H.J. Thomps. & J.E. Roberts

Raven's blazing-star

Print Report

Taxon Summary

Mentzelia ravenii, commonly known as Raven's blazing-star, is a annual herb in the Loasaceae that is found only in California. It occurs within Joshua tree "woodland", Mojavean desert scrub, and Pinyon and juniper woodland, growing at elevations from 800 to 1100 meters. Mentzelia ravenii is ranked 1B.3, Plants Rare, Threatened or Endangered in California and Elsewhere; Not very threatened in California.

Classification


Scientific Name:	Mentzelia ravenii H.J. Thomps. & J.E. Roberts
Common Name:	Raven's blazing-star
Family:	Loasaceae
Element Code:	PDLOA033A0
USDA Plants Symbol:	MERA
Synonyms/Other Names:

Ecology and Life History


Lifeform:	annual herb
Blooming Period: Mar-May	Mar-May
Elevation:	800-1100 (2625-3610)
General Habitats:	Joshua tree "woodland", Mojavean desert scrub, Pinyon and juniper woodland
Microhabitat:	Decomposed granitic, Flats, Gravelly, Roadsides, Sandy, Slopes, Washes
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.3
Global Rank:	GNR
State Rank:	S2
State List:	None
Fed List:	None
Other Status:
CRPR Changes:	added to 1B.3 on 2025-03-11

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)

Quads: Name (Quad Code)

Threat List Data from the CNDDB


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

Notes




Threats:
Potentially threatened by development, habitat loss, road maintenance, and vehicles.
Taxonomy:
An allotetraploid with Mentzelia congesta being the maternal parent and the paternal parent unresolved. Similar to M. gracilenta but differing eco-geographically and by its somewhat smaller flowers. Often co-occurs with M. veatchiana but differing by its habit spreading or candelabriform (vs. strictly erect), petals yellow with orange spot at base (vs. usually deep orange in desert populations), and floral bracts broad and often somewhat clasping (vs. narrow and not clasping). Populations from RIV and SDG cos. need further study to determine whether they should be included in M. ravenii or are distinct taxa.

Selected References

Proposed addition to CRPR 1B.3, G2 / S2 (2025)

Phytologia 21(4): 285

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].