Species Details

Hemizonia congesta ssp. congesta

congested-headed hayfield tarplant

  Download Report   Calflora    eFlora    CCH    CalPhotos  
Photo of Hemizonia congesta ssp. congesta
© 2015 Vernon Smith
Photo of Hemizonia congesta ssp. congesta
© 2015 John Doyen
Photo of Hemizonia congesta ssp. congesta
© 2015 Vernon Smith
CA Rare Plant Rank: 1B.2
Fed List: None
State List: None
Global Rank: G5T2
State Rank:
Other Status: SB_UCBG
CRPR Changes:
changed from 3 to 1B.2 on 2008-09-30
Add Date: 1988-01-01
Date Edited: 2023-06-06
Lifeform: annual herb
Blooming Period: Apr-Nov
20 - 560 meters
65 - 1835 feet
General Habitats:
  • Valley and foothill grassland
Microhabitat Details:
  • Roadsides (sometimes)
Threatened by agriculture, development, and road construction. Possibly threatened by grazing. Hybridizes with H. congesta ssp. lutescens. See H. congesta ssp. leucocephala in The Jepson Manual (1993). What was once considered H. congesta ssp. congesta in The Jepson Manual (1993) is now considered H. congesta ssp. lutescens; a common taxon.
Threat List Total: 8
Total EOs % of EOs
EOs with Threat Listed: 19 37 %
Development 13 25%
Grazing 4 7%
Non-native plant impacts 3 5%
Foot traffic/trampling 2 3%
Agriculture 1 1%
Total Occurrences: 52
Element Occurrence Ranks:
1 5 3 1 4 38
Occurrence Status:
Historical >20 Years 40
Recent <=20 Years 12
Presumed Extant 48
Possibly Extirpated 3
Presumed Extirpated 1
California Endemic:
California Island:
States: Name (Code)
California (CA)
California Counties and Islands: Name (Code)
Lake (LAK), Marin (MRN), Mendocino (MEN), San Francisco (SFO), San Mateo (SMT), Sonoma (SON)
Quads: Name (Quad Code)
Arched Rock (3812342), Bodega Head (3812331), Bolinas (3712286), Camp Meeker (3812248), Cloverdale (3812371), Cotati (3812236), Glen Ellen (3812235), Healdsburg (3812257), Hunters Point (3712263), Inverness (3812217), Mark West Springs (3812256), Middletown (3812275), Novato (3812215), Noyo Hill (3912346), Oakland West (3712273), Petaluma (3812226), Petaluma River (3812225), Point Bonita (3712275), Point Reyes NE (3812227), San Francisco North (3712274), San Francisco South (3712264), San Geronimo (3812216), San Rafael (3712285), Santa Rosa (3812246), Sebastopol (3812247), Sonoma (3812234), Tomales (3812228), Two Rock (3812237), Valley Ford (3812238), Warm Springs Dam (3812361)
Definitions of codes following a county and/or quad:
* Presumed extirpated
(?) Occurrence confirmed, but possibly extirpated
Quad and county data is imported from the CNDDB. Species may be present in other areas where conditions are favorable. These data should NOT be substituted for pre-project review or for on-site surveys.
Presumed Extant
Click on quad for name. Hold Shift Key to use mouse scroll wheel