Taxon Report

Centromadia parryi (Greene) Greene ssp. australis (Keck) B.G. Baldwin

southern tarplant

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Taxon Summary

Centromadia parryi ssp. australis, commonly known as southern tarplant, is a annual herb in the Asteraceae that is found in California and elsewhere. It occurs within Marshes and swamps (margins), Valley and foothill grassland (vernally mesic), and Vernal pools, growing at elevations from 0 to 480 meters. Centromadia parryi ssp. australis is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.


  Classification

Scientific Name:
Centromadia parryi (Greene) Greene ssp. australis (Keck) B.G. Baldwin
Common Name:
southern tarplant
Family: Asteraceae
Element Code: PDAST4R0P4
USDA Plants Symbol: CEPAA
Synonyms/Other Names:
  • Hemizonia parryi Greene ssp. australis Keck

Ecology and Life History

Lifeform: annual herb
Blooming Period: May-Nov May-Nov
Elevation: 0-480 (0-1575)
General Habitats: Marshes and swamps, Valley and foothill grassland, Vernal pools
Microhabitat:
Microhabitat Details:

Occurrence Data from the CNDDB

Total Occurrences: 94
Element Occurrence Ranks:
   Excellent (A) 3
   Good (B) 17
   Fair (C) 11
   Poor (D) 4
   None (X) 10
   Unknown (U) 49
California Endemic:  False
California Counties and Islands: Name (Code)
Los Angeles (LAX), Orange (ORA), San Diego (SDG), Santa Barbara (SBA), Ventura (VEN)
Quads: Name (Quad Code)
Anaheim (3311778), Baldwin Park (3411718), Beverly Hills (3411814)*, Canada Gobernadora (3311755), Del Mar (3211782), Dos Pueblos Canyon (3411948), El Monte (3411811), Escondido (3311711), Goleta (3411947), Hollywood (3411813)*, Inglewood (3311883)*, Laguna Beach (3311757), Long Beach (3311872)*, Los Alamitos (3311871), Morro Hill (3311733), Mt. Wilson (3411821), Newbury Park (3411828), Newport Beach (3311768), Orange (3311777), Pasadena (3411822)*, Pitas Point (3411934)(?), San Marcos (3311722), San Pasqual (3311618), Santa Catalina East (3311833)?, Seal Beach (3311861), South Gate (3311882)*, Sunland (3411833), Torrance (3311873), Tustin (3311767), Valley Center (3311721), Venice (3311884)*

Threat List Data from the CNDDB

Threat List Total: 16
EOs with Threat Listed: Total EOs % of EOs
43 46 %
Development 20 21%
Other 14 14%
Foot traffic/trampling 11 11%
Road/trail construction/maint. 10 10%
Non-native plant impacts 7 7%
ORV activity 6 6%
Disking 6 6%
Recreational use (non-ORV) 5 5%
Vandalism/dumping/litter 4 4%
Agriculture 3 3%
Grazing 3 3%
Waterway bank protection/maintenance 2 2%
Wood cutting or brush clearing 1 1%
Hybridization 1 1%
Military operations 1 1%
Mining 1 1%

Notes

Need confirmation of SCT Isl. occurrences. Many ORA Co. occurrences recently extirpated. Many historical occurrences also extirpated; need information. Population fragmentation a serious problem, and plant continues to be threatened by urbanization, vehicles, development, foot traffic, grazing, habitat disturbance, and competition from non-native plants. A synonym of Hemizonia parryi ssp. australis in TJM (1993). See MadroƱo 3(1):15 (1935) for original description, and Novon 9:462-471 (1999) for revised nomenclature.
Threats:
Taxonomy:
Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 5 February 2025].