CPC Plant Profile: Santa Ana River Woolstar
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Plant Profile

Santa Ana River Woolstar (Eriastrum densifolium ssp. sanctorum)

This shot shows the plants, highlighting the distinctive blue flowers. Photo Credit: Michael Wall
Description
  • Global Rank: T1 - Critically Imperiled
  • Legal Status: Federally Endangered
  • Family: Polemoniaceae
  • State: CA
  • Nature Serve ID: 161697
  • Date Inducted in National Collection: 03/14/1986

This endangered blue-flowered phlox species is restricted to sandy floodplain areas in Southern California and was listed as Federally Endangered in 1987. Remaining populations are threatened by flood control and competition with a non-native species, river cane (Arundo donax). In 1988, a preservation area was established by the U.S. Army Corps of Engineers in an undeveloped portion of land in San Bernardino National Forest that includes 309 hectares (764 acres) of suitable habitat for Eriastrum densifolium ssp. sanctorum. The biggest threat to this species is the construction of the Seven Oaks dam, which is currently in progress, which will substantially reduce the historic floodplain areas that this species lives on. This shrub can grow to one meter (3.3 feet) tall, with gray-green stems and leaves. It produces bright blue flowers that are up to 1.4 inches long that occur in flower heads with about 20 blossoms each. (USFWS 1986)

Participating Institutions
Updates
  • 09/09/2020
  • Reproductive Research

Anatomical features of Eriastrum densifolium subspecies from populations in Southern California have shown variation in their morphological features that correlate with their specific habitats and can be used in differentiating subspecies (Brunell and Whitkus 1997, 1998). When crossed with other Eriastrum species, Eriastrum densifolium ssp. sanctorum showed exhibited a high infertility rate (Brunell and Whitkus 1999). Graduate students have studied a number of subjects relating to this species (Phommasaysy 1999, Brunell 1996, Stone 1995, Erickson 1994, Wheeler 1991, Munoz 1991, Brunell 1991)

  • 09/01/2020
  • Orthodox Seed Banking

Based on an September 2020 extract of the California Plant Rescue Database, California Botanic Garden holds 5 accessions of Eriastrum densifolium subsp. sanctorum in orthodox seed collection. There are as many as 82985 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 4 seed accessions of Eriastrum densifolium subsp. sanctorum from 1 plant occurrences listed in the California Natural Diversity Database. These collections together emcompass 760 maternal plants

Nature Serve Biotics
  • 05/02/2017

Eriastrum densivolium ssp. sanctorum is endemic to the Santa Ana River drainage of San Bernardino, Riverside and Orange Counties. Extirpated in Orange County, the beautiful perennial with large lavender flowers is known from several fragmented, damaged occurrences. Intensive use of the flood plain margins has resulted in alteration of habitat and habitat that is totally unsuitable. The Santa Ana River woollystar is also threatened by development, sand and gravel mining, flood control projects, non-native plant competition, intensive grazing, and farming. There are no protected EO's to speak of. The overall trend is very much downhill.

Rancho Santa Ana Botanic Garden
  • 01/01/2010

Threats include general urbanization, highway construction and maintenance, off-road-vehicles, flood control work, sand and gravel mining and grazing and competition from the non-native river cane (Arundo donax).

Rancho Santa Ana Botanic Garden
  • 01/01/2010

Known from approximately 20 populations.

Rancho Santa Ana Botanic Garden
  • 01/01/2010

Anatomical features of Eriastrum densifolium subspecies from populations in Southern California have shown variation in their morphological features that correlate with their specific habitats and can be used in differentiating subspecies (Brunell and Whitkus 1997, 1998). When crossed with other Eriastrum species, Eriastrum densifolium ssp. sanctorum showed exhibited a high infertility rate (Brunell and Whitkus 1999). Graduate students have studied a number of subjects relating to this species (Phommasaysy 1999, Brunell 1996, Stone 1995, Erickson 1994, Wheeler 1991, Munoz 1991, Brunell 1991)

Rancho Santa Ana Botanic Garden
  • 01/01/2010

Proposed management plans include the removal of the non-native river cane and modification of flood control management.

Rancho Santa Ana Botanic Garden
  • 01/01/2010

Not Available

Rancho Santa Ana Botanic Garden
  • 01/01/2010

Not Available

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Photos
Nomenclature
Taxon Eriastrum densifolium ssp. sanctorum
Authority (Milliken) Mason
Family Polemoniaceae
CPC Number 1618
ITIS 31054
USDA ERDES
Common Names Santa Ana River eriastrum | Santa Ana River woolly-star | Santa Ana woolly-star | giant woolstar
Associated Scientific Names Eriastrum densifolium ssp. sanctorum | Gilia densifolia var. sanctora | Hugelia densifolia var. sanctora
Distribution Endemic to the Santa Ana River Drainage in San Bernardino and Riverside County in southern California.
State Rank
State State Rank
California S1
Habitat

Sandy river floodplain along the Santa Ana River in California. This alluvial fan supports another Center for Plant Conservation taxon, the slender-horned spineflower (Dodecahema leptoceras). (CDFG 2002)

Ecological Relationships

Pollinators
Common Name Name in Text Association Type Source InteractionID

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