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Plant Profile

California Golden-banner (Thermopsis macrophylla)

Mature plants can produce as many as 10 flowering stalks, each with 90-100 yellow flowers that can produce 6-8 seeds each, meaning that a full-grown plant can produce up to 8000 seeds a year. Photo Credit: Dieter Wilken
  • Global Rank: G1 - Critically Imperiled
  • Legal Status: N/A
  • Family: Fabaceae
  • State: CA
  • Nature Serve ID: 150279
  • Lifeform: Forb/herb
  • Date Inducted in National Collection:
Description:

Fewer than 2500 plants survive within a relatively narrow band about 3 miles long along the crest of the central Santa Ynez Mountains in Santa Barbara County, California. Current populations consist of plants similar in age and may be several decades old, because seeds germinate only after historically infrequent fires. Plants are the largest in the genus Thermopsis, are up to 1 meter wide, and are up to 2 meters tall when in full bloom. Leaves appear in the late winter, forming large clusters near the base. Each plant may produce up to 10 flowering stalks, each bearing between 90 and 100 flowers that are 2 cm long. (Chen et al. 1994)

Where is California Golden-banner (Thermopsis macrophylla) located in the wild?

Habitat:

Open sites on gravelly to rocky substrates derived from sandstone at an altitude of 1000 - 1400 meters. Common chaparral associates include Adenostoma fasciculatum, Arctostaphylos glandulosa, and Ceanothus leucodermis. Populations occur on open sites that experience wet winters, hot summer days, and foggy summer nights.

Distribution:

Santa Ynez Mountains, Santa Barbara County, California

States & Provinces:

California Golden-banner can be found in California

Which CPC Partners conserve California Golden-banner (Thermopsis macrophylla)?

  • Santa Barbara Botanic Garden

    Not Sponsored
    Conservation Actions
    Assigned 06/09/17
    • CPC's Plant Sponsorship Program provides long term stewardship of rare plants in our National Collection. We are so grateful for all our donors who have made the Plant Sponsorship Program so successful. We are in the process of acknowledging all our wonderful plant sponsorship donors on our website. This is a work in progress and will be updated regularly.

    Conservation Actions

    Center for Plant Conservation
    • 08/20/2021
      • Orthodox Seed Banking

    In 2021, CPC contracted Santa Barbara Botanic Garden to recollect seed from a population currently held in long term orthodox seed storage as part of an IMLS-funded seed longevity experiment. The National Laboratory for Genetic Resources Preservation will evaluate how germination tested viability and RNA Integrity of seed lots decline over time in storage.

    • 09/30/2020
      • Propagation Research

    Studies are being conducted by the Santa Barbara Botanic Garden on germination rates following short-term cold storage.

    • 09/01/2020
      • Orthodox Seed Banking

    Based on an September 2020 extract of the California Plant Rescue Database, Santa Barbara Botanic Garden holds 15 accessions of Thermopsis macrophylla in orthodox seed collection. There are as many as 13900 seeds of this species in their collection - although some may have been used for curation testing or sent to back up.

    • 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 Thermopsis macrophylla in orthodox seed collection. There are as many as 2374 seeds of this species in their collection - although some may have been used for curation testing or sent to back up.

    • 09/01/2020
      • Orthodox Seed Banking

    Based on an September 2020 extract of the California Plant Rescue Database, National Laboratory for Genetic Resource Preservation (USDA-ARS) holds 1 accessions of Thermopsis macrophylla in orthodox seed collection. There are as many as 2000 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, Santa Barbara Botanic Garden has collected 16 seed accessions of Thermopsis macrophylla from 2 plant occurrences listed in the California Natural Diversity Database. These collections together emcompass 339 maternal plants

    • 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 Thermopsis macrophylla from 1 plant occurrences listed in the California Natural Diversity Database. These collections together emcompass an unknown number of maternal plants

    Nature Serve Biotics
    • 05/02/2017

    Endemic to Santa Barbara County, California and known from fewer than 7 occurrences. Although seven sites are documented, only one is confirmed extant. Apparently disturbance dependent and fire suppression is the primary threat. Historic sites need to be surveyed.

    Dieter Wilken, Ph.D.
    • 01/01/2010

    Habitat disturbance and loss of plants along roads and off-road mountain bike trails. Proposed 300-foot-wide fire break. Potential perturbation of natural fire cycles. Competition at seedling stage from annual exotic grasses. Damage to plants by

    Dieter Wilken, Ph.D.
    • 01/01/2010

    Single individuals and colonies consisting of 3-150 plants are dispersed as patches within a narrow, oblong area about 3 miles long. The number of plants are estimated to be between 2,000 and 2,500. A small disjunct population of less than 10 plants occurs about 15 miles distant in the same mountain range. Reports of other plants in the Santa Ynez Mountains have not been substantiated by recent surveys, and reports from other mountain ranges in California are based on misidentifications.

    Dieter Wilken, Ph.D.
    • 01/01/2010

    Studies are being conducted by the Santa Barbara Botanic Garden on germination rates following short-term cold storage. Populations are monitored annually to estimate numbers, reproductive rates, and pollinator visitation.

    Dieter Wilken, Ph.D.
    • 01/01/2010

    All known plants occur on lands managed by the Los Padres National Forest. Parking along the road in the vicinity of plants is limited or restricted, and motorized off-highway vehicles are prohibited.

    Dieter Wilken, Ph.D.
    • 01/01/2010

    Genetic analysis within and among populations. Ecological factors determining successful establishment of plants from seeds. A management plan that increases the number of plants and ensures stable population structure.

    Dieter Wilken, Ph.D.
    • 01/01/2010

    Additional collections of seeds, segregated by maternal plants, representing the entire geographic distribution.

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    Nomenclature
    Taxon Thermopsis macrophylla
    Authority Hook. & Arn
    Family Fabaceae
    CPC Number 15994
    ITIS 27001
    USDA THMA2
    Duration Perennial
    Common Names Santa Ynez false lupine | Santa Ynez goldenbanner
    Associated Scientific Names Thermopsis macrophylla | Thermopsis macrophylla var. macrophylla | Thermopsis macrophylla var. agnina
    Distribution Santa Ynez Mountains, Santa Barbara County, California
    State Rank
    State State Rank
    California S1
    Ecological Relationships

    Photos

    Mature plants can produce as many as 10 flowering stalks, each with 90-100 yellow flowers that can produce 6-8 seeds each, meaning that a full-grown plant can produce up to 8000 seeds a year. Photo Credit: Dieter Wilken

    Plants are self-compatible, and are actively visited by bumblebees and carpenter bees. Photo Credit: Dieter Wilken

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