Taxon Report

Astragalus tener Gray var. ferrisiae Liston

Ferris' milk-vetch

Print Report

Taxon Summary

Astragalus tener var. ferrisiae, commonly known as Ferris' milk-vetch, is a annual herb in the Fabaceae that is found only in California. It occurs within Meadows and seeps (vernally mesic), and Valley and foothill grassland (subalkaline flats), growing at elevations from 2 to 75 meters. Astragalus tener var. ferrisiae is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.

Classification


Scientific Name:	Astragalus tener Gray var. ferrisiae Liston
Common Name:	Ferris' milk-vetch
Family:	Fabaceae
Element Code:	PDFAB0F8R3
USDA Plants Symbol:	ASTEF
Synonyms/Other Names:

Ecology and Life History


Lifeform:	annual herb
Blooming Period: Apr-May	Apr-May
Elevation:	2-75 (5-245)
General Habitats:	Meadows and seeps, Valley and foothill grassland
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.1
Global Rank:	G2T1
State Rank:	S1
State List:	None
Fed List:	None
Other Status:	BLM_S
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	18
Element Occurrence Ranks:
Excellent (A)	1
Good (B)	0
Fair (C)	0
Poor (D)	1
None (X)	5
Unknown (U)	11

Location


California Endemic: True
California Counties and Islands: Name (Code)
Butte (BUT), Colusa (COL), Glenn (GLE), Solano (SOL)*, Sutter (SUT), Yolo (YOL), Yuba (YUB)
Quads: Name (Quad Code)
Arbuckle (3912211), Butte City (3912148), Colusa (3912221), Davis (3812156), Dozier (3812137), Dunnigan (3812188), Grimes (3912118), Llano Seco (3912158), Logandale (3912242), Manor Slough (3912223), Merritt (3812157), Nord (3912178), Olivehurst (3912115), Pennington (3912137), Sacramento West (3812155), Saxon (3812146), Sutter (3912126), West of Biggs (3912147), Wildwood School (3812281), Yuba City (3912125)

Threat List Data from the CNDDB


Threat List Total:	5
EOs with Threat Listed:	Total EOs	% of EOs
	8	44 %
Agriculture	6	33%
Grazing	2	11%
Non-native plant impacts	1	5%
Other	1	5%
Surface water diversion	1	5%

Notes



Rediscovered in 1989 by V. Oswald in Butte Sink WA (DFG). Most historical habitat destroyed by agriculture. See Brittonia 42(2):100-104 (1990) for original description, and Systematic Botany 17(3):367-379 (1992) for distributional information.
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 14 November 2025].