CPC Plant Profile: Big Tarweed
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Plant Profile

Big Tarweed (Blepharizonia plumosa)

Photo Credit: ©2016 Neal Kramer
  • Global Rank: T2 - Imperiled
  • Legal Status: N/A
  • Family: Asteraceae
  • State: CA
  • Nature Serve ID: 130640
  • Date Inducted in National Collection: 09/18/2021

Blepharizonia plumosa, or the big tarweed, is an annual herb that is currently threatened by urbanization, residential development, and non-native plant growth. Little is known about B. plumosa but it blooms in clay soils from mid summer into the fall in valley grasslands across Contra Costa, Alameda, and Stanislaus counties. Its conservation status is under review but, for now, it is being identified as “apparently secure”.   

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 Blepharizonia plumosa in orthodox seed collection. There are as many as 1008 seeds of this species in their collection - although some may have been used for curation testing or sent to back up.

  • 08/05/2020
  • Seed Collection

Based on an August 2020 extract of the California Plant Rescue Database, California Botanic Garden has collected 1 seed accessions of Blepharizonia plumosa from 1 plant occurrences listed in the California Natural Diversity Database. These collections together emcompass 20 maternal plants

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Taxon Blepharizonia plumosa
Authority (Kellogg) Greene
Family Asteraceae
CPC Number 8088
ITIS 36849
Common Names Big Tarweed
Associated Scientific Names Blepharizonia plumosa | Blepharizonia plumosa var. plumosa | Calycadenia plumosa | Hemizonia plumosa | Hemizonia plumosa var. plumosa
State Rank
State State Rank
California S2

It prefers valley/foothill grasslands where it thrives on clay soil

Ecological Relationships

Common Name Name in Text Association Type Source InteractionID

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