Taxon Report

Eriogonum giganteum Wats. var. compactum Dunkle

Santa Barbara Island buckwheat

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Taxon Summary

Eriogonum giganteum var. compactum, commonly known as Santa Barbara Island buckwheat, is a perennial deciduous shrub in the Polygonaceae that is found only in California. It occurs within Coastal bluff scrub, growing at elevations from 10 to 300 meters. Eriogonum giganteum var. compactum is ranked 1B.3, Plants Rare, Threatened or Endangered in California and Elsewhere; Not very threatened in California.


  Classification

Scientific Name:
Eriogonum giganteum Wats. var. compactum Dunkle
Common Name:
Santa Barbara Island buckwheat
Family: Polygonaceae
Element Code: PDPGN082A1
USDA Plants Symbol: ERGIC
Synonyms/Other Names:

Ecology and Life History

Lifeform: perennial deciduous shrub
Blooming Period: May-Aug(Sep) May-Aug(Sep)
Elevation: 10-300 (35-985)
General Habitats: Coastal bluff scrub
Microhabitat:
Microhabitat Details:

Occurrence Data from the CNDDB

Total Occurrences: 4
Element Occurrence Ranks:
   Excellent (A) 0
   Good (B) 3
   Fair (C) 0
   Poor (D) 0
   None (X) 0
   Unknown (U) 1
California Endemic:  True
California Counties and Islands: Name (Code)
Santa Barbara (SBA)
Quads: Name (Quad Code)
Santa Barbara Island (3311848)

Threat List Data from the CNDDB

Threat List Total: 3
EOs with Threat Listed: Total EOs % of EOs
3 75 %
Erosion/runoff 2 50%
Foot traffic/trampling 1 25%
Other 1 25%

Notes

Known from fewer than 10 occurrences, but population numbers are increasing. Threatened by non-native plants. See Bulletin of the Southern California Academy of Sciences 41:130 (1943) for original description, and Phytologia 66(4):318-319 (1989) for taxonomic treatment.
Threats:
Taxonomy:
Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 9 May 2025].