Coastal southern California from Peninsular Range foothills of Orange, Riverside, and San Diego Counties to Baja California, Mexico [1,2].
Known Populations in San Diego County
Eight occurrences on Conserved lands in MUs 3 (South Crest, McGinty Mountain, Sycuan Peak Ecological Reserve), 6 (San Marcos Mountains) and 8 (Merriam Mountains, Monserate Mountain, Wilderness Gardens).
Occurs on dry, stony slopes composed of gabbro-derived soils in chaparral and coastal scrub communities[3; cited from 4]. Elevation range is 165-1,000 meters . Low-growing chamise chaparral, with moderately dense canopy cover .
Taxonomy and genetics
Picrodendraceae family .
Life history demography
Perennial deciduous shrub .
Blooms April to May .
Threatened by agriculture and development .
Parry's tetracoccus sources
 Webster, G. L. 2016. “Tetracoccus Dioicus.” Jepson eFlora. http://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=46211.
 CNPS, Rare Plant Program. 2016. Inventory of Rare and Endangered Plants (online edition, v8-02). California Native Plant Society, Sacramento, CA. http://www.rareplants.cnps.org, accessed 29 August 2016.
 California Native Plant Society. 2001. Inventory of Rare and Endangered Plants of California (Sixth Edition). Edited by Rare Plant Scientific Advisory Committee David P. Tibor Convening Editor. 6th ed. Sacramento, CA.
 Gibson, C. E. 2003. “Viability Assessment: Tetracoccus Dioicus Parry.”
 San Diego County Water Authority, Sweetwater Authority, Helix Water District, City of Poway Public Works Department, and Santa Fe Irrigation District. 2015. “Final Mitigated Negative Declaration and Initial Study/ Environmental Checklist Application of Copper-Based Algaecides at Five Reservoirs San Diego County California.”