CPC Plant Profile: Pappose Spikeweed
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Plant Profile

Pappose Spikeweed (Centromadia parryi ssp. congdonii)

Photo Credit: ©2011 Neal Kramer
  • Global Rank: T2 - Imperiled
  • Legal Status: N/A
  • Family: Asteraceae
  • State: CA
  • Nature Serve ID: 152587
  • Date Inducted in National Collection: 09/22/2021

Also known as the Congdon’s tarplant, Centromadia parryi ssp. congdonii is a tarweed subspecies that is endemic to the northern California coast. Like its southern subspecies (C. p. ssp. australis), C. p. ssp. congdonii is a grassland herb that blooms yellow florets annually in heavy alkaline soil between May and October. It favors sea level elevations but has been seen as high up as 200m.

Participating Institutions
  • 09/01/2020
  • Orthodox Seed Banking

Based on an September 2020 extract of the California Plant Rescue Database, California Botanic Garden holds 1 accessions of Centromadia parryi subsp. congdonii in orthodox seed collection. There are as many as 168078 seeds of this species in their collection - although some may have been used for curation testing or sent to back up.

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Taxon Centromadia parryi ssp. congdonii
Authority (B.L. Rob. & Greenm.) B.G. Baldwin
Family Asteraceae
CPC Number 44938
ITIS 780716
Common Names pappose spikeweed | Congdon's tarplant
Associated Scientific Names Hemizonia parryi ssp. congdonii | Centromadia parryi ssp. congdonii | Hemizonia congdonii | Centromadia congdonii | Hemizonia parryi var. congdonii | Centromadia pungens var. congdonii
Distribution This subspecies of tarweed can primarily be found in Contra Costa, Alameda, and northern Monterey counties. There are also scattered occurrences in San Mateo, Santa Clara, Santa Cruz, and Solano counties. It is mainly a northern California herb, recorded sightings have been confirmed as far south as San Luis Obispo county.
State Rank
State State Rank
California S2

C. p. ssp. congdonii shares the same habitat preferences as its southern subspecies C. p. ssp. australis: sea level grasslands with heavy alkaline soil. 

Ecological Relationships

Common Name Name in Text Association Type Source InteractionID

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