CPC Plant Profile: Cuesta Pass Sidalcea
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Plant Profile

Cuesta Pass Sidalcea (Sidalcea hickmanii ssp. anomala)

This closeup shot shows buds and flowers above bracts. Photo Credit: Dieter Wilken
Description
  • Global Rank: T1 - Critically Imperiled
  • Legal Status: N/A
  • Family: Malvaceae
  • State: CA
  • Nature Serve ID: 141736
  • Date Inducted in National Collection: 03/06/1993

Cuesta Pass Sidalcea has multiple, ascending stems from 0.4 to 1 m long. Each stem bears many flowers, which are less than 1 inch in diameter and have bright pinkish lavender petals. This species is a typical "fire follower", with 1000's of plants reported within the first 2-3 years following a chaparral fire. However, most populations appear to have relatively few plants after 5 or more years following such fires. Regardless, the documented distribution is restricted to about 4-5 occurrences in an area of no more than 5 square kilometers.

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

Based on an September 2020 extract of the California Plant Rescue Database, California Botanic Garden holds 13 accessions of Sidalcea hickmanii subsp. anomala in orthodox seed collection. There are as many as 2789 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, Santa Barbara Botanic Garden holds 2 accessions of Sidalcea hickmanii subsp. anomala in orthodox seed collection. There are as many as 400 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 2 seed accessions of Sidalcea hickmanii subsp. anomala from 2 plant occurrences listed in the California Natural Diversity Database. These collections together emcompass 22 maternal plants

Nature Serve Biotics
  • 05/02/2017

Sidalacea hickmanii ssp. anomala is a very narrowly restricted subspecies. It is found on serpentine soils near mine spoils in chaparral and the margins of cypress woodlands (CPC 2010). This subspecies seems to require fire to flourish, however, only one of the three occurrences has been burned in the last 20 years. Number of individuals at this occurrence did rapily rise after the fire, which is an encouraging sign that this subspecies could be actively managed. With this said, however, reports of number of individuals has decreased since the early 2000s. The three occurrences are threatened by construction, erosion, cattle and other animals, and probably the greatest threat is lack of fire. Overall, active management and protection for this species is needed given its small area of occupancy, tiny range extent, and threats.

Dieter Wilken, Ph.D.
  • 01/01/2010

Potential mine reclamation at some sites may have an adverse effect. Erosion at some road cuts and adjacent trenches.

Dieter Wilken, Ph.D.
  • 01/01/2010

Known from 4-5 occurrences, each with 20 to over 100 individual plants. Censuses conducted within 1-2 years following fires reveal higher number of plants, suggesting that this species appears to be more abundant after fires and that it is usually represented by a substantial seed bank. (CDFG 2002)

Dieter Wilken, Ph.D.
  • 01/01/2010

Populations on Camp San Luis Obispo are being monitored.

Dieter Wilken, Ph.D.
  • 01/01/2010

Some populations in the Los Padres National Forest are protected within the Cuesta Ridge Botanical Area. Populations on land managed by the California National Guard (Camp San Luis Obispo) are in restricted areas, but proposed mine reclamation may adversely affect some populations.

Dieter Wilken, Ph.D.
  • 01/01/2010

Genetic variation within and among populations. Studies of the breeding system and seed biology, including germination requirements.

Dieter Wilken, Ph.D.
  • 01/01/2010

Seed collections from all known populations.

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Photos
Nomenclature
Taxon Sidalcea hickmanii ssp. anomala
Authority C.L. Hitchc.
Family Malvaceae
CPC Number 3974
ITIS 524688
USDA SIHIA
Common Names Cuesta Pass checkerbloom | Cuesta Pass sidalcea | Cuesta Pass checker
Associated Scientific Names Sidalcea hickmanii ssp. anomala
Distribution Santa Lucia Mountains north of San Luis Obispo. (Hitchcock 1957)
State Rank
State State Rank
California S1
Habitat

Open rocky slopes and talus composed of serpentine, sometimes near abandoned mine spoils and near roads, in chaparral and at the margins of cypress woodlands. Common associates include Quercus durata, Arctostaphylos obispoensis, Ceanothus spp., and Cupressus sargentii. (Hitchcock 1957)

Ecological Relationships

Cuesta Pass Sidalcea occurs exclusively on serpentine substrates. Plants are self-compatible but require insect visitation to set seeds. Each flower can produce up to 8 seeds, but many fruits are often empty, or produce only a few seeds. Unlike other fire-adapted chaparral plants, the seeds do not have exceptionally hard coats and may germinate readily under conditions not yet understood. Although the longevity of seeds in the soil is not known, a considerable seed bank may be present. Following fires, high densities of plants have been observed, but a substantial number of flowering shoots may arise from previously established rhizome systems (E. Painter pers. comm.). As dominant vegetation re-establishes cover on burned sites, the number of flowering shoots declines and plants often appear to be widely scattered.

Pollinators
Common Name Name in Text Association Type Source InteractionID

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