Taxon Report

Tropidocarpum capparideum Greene

caper-fruited tropidocarpum

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Taxon Summary

Tropidocarpum capparideum, commonly known as caper-fruited tropidocarpum, is a annual herb in the Brassicaceae that is found only in California. It occurs within Valley and foothill grassland, growing at elevations from 1 to 455 meters. Tropidocarpum capparideum is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.

Classification


Scientific Name:	Tropidocarpum capparideum Greene
Common Name:	caper-fruited tropidocarpum
Family:	Brassicaceae
Element Code:	PDBRA2R010
USDA Plants Symbol:	TRCA9
Synonyms/Other Names:

Ecology and Life History


Lifeform:	annual herb
Blooming Period: Mar-Apr	Mar-Apr
Elevation:	1-455 (5-1495)
General Habitats:	Valley and foothill grassland
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.1
Global Rank:	G1
State Rank:	S1
State List:	None
Fed List:	None
Other Status:	SB_CalBG/RSABG; USFS_S
CRPR Changes:	added to 1B on 2003-05-07

Occurrence Data from the CNDDB


Total Occurrences:	20
Element Occurrence Ranks:
Excellent (A)	1
Good (B)	4
Fair (C)	0
Poor (D)	0
None (X)	9
Unknown (U)	6

Location


California Endemic: True
California Counties and Islands: Name (Code)
Alameda (ALA), Contra Costa (CCA), Monterey (MNT), San Joaquin (SJQ)*, San Luis Obispo (SLO)
Quads: Name (Quad Code)
Altamont (3712166), Brentwood (3712186), Burnett Peak (3512172), Byron Hot Springs (3712176), Clayton (3712188), Clifton Court Forebay (3712175), Jolon (3512182), Lathrop (3712173), Livermore (3712167), Lopez Mtn. (3512035), Midway (3712165), Tassajara (3712177), Tracy (3712164), Union Island (3712174), Woodward Island (3712185)*

Threat List Data from the CNDDB


Threat List Total:	8
EOs with Threat Listed:	Total EOs	% of EOs
	15	75 %
Agriculture	8	40%
Development	5	25%
Military operations	5	25%
Non-native plant impacts	3	15%
ORV activity	1	5%
Grazing	1	5%
Improper burning regime	1	5%
Altered flood/tidal/hydrologic regime	1	5%

Notes



Rediscovered in 2000 on Ft. Hunter Liggett (DOD). Possibly threatened by grazing, military activities, trampling, and non-native plants. See Pittonia 1:217 (1888) for original description, and Novon 11:292-293 (2001) for taxonomic information.
Threats:

Taxonomy:

Selected References

CRPR List Addition on 2003-05-07

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 15 November 2025].