Home/Species/ San Joaquin Adobe Sunburst

Pseudobahia peirsonii

Munz

San Joaquin Adobe Sunburst

G1Critically Imperiled Found in 2 roadless areas NatureServe Explorer →

G1Critically ImperiledGlobal Rank

Very highThreat Impact

Identity

Unique IDELEMENT_GLOBAL.2.144905

Element CodePDAST7P030

Record TypeSPECIES

ClassificationSpecies

Classification StatusStandard

Name CategoryVascular Plant

Endemicendemic to a single state or province

KingdomPlantae

PhylumAnthophyta

ClassDicotyledoneae

OrderAsterales

FamilyAsteraceae

GenusPseudobahia

Concept Reference

Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.

Conservation Status

Rank Method Rank calculation - Biotics v2

Review Date2026-03-27

Change Date2013-08-20

Edition Date2026-03-27

Edition AuthorsMaybury, K. (1997), rev. (2017), rev. Soteropoulos (2026)

Threat ImpactVery high

Range Extent1000-5000 square km (about 400-2000 square miles)

Number of Occurrences6 - 20

Rank Reasons

Pseudobahia peirsonii is an annual herb found in adobe clay soils within valley and foothill grasslands, and occasionally grassland-blue oak woodland community ecotones and openings of foothill (cismontane) woodlands. It is endemic to the western United States in the southeastern Central Valley of California in the southern Sierra Nevada Foothills and southeastern San Joaquin Valley. There are nineteen occurrences, though most have very small populations with fewer than 250 individuals. The primary threats to this species are conversion of habitat and habitat fragmentation from residential and agricultural development, with additional threats from road and transmission line maintenance projects, mining, recreational activities, and competition from non-native plants. Continued monitoring, especially of populations on private properties, is needed, and seeking protection of these privately owned populations through acquisition or management agreements is a high priority.

Range Extent Comments

Pseudobahia peirsonii is endemic to the western United States in the southeastern Central Valley of California in the southern Sierra Nevada Foothills and southeastern San Joaquin Valley, where it has been documented in Fresno, Kern, and Tulare (FNA 2006, Jepson Flora Project 2026). Range extent was estimated to be 4148 square kilometers using herbarium specimens and NatureServe Network occurrence data documented between 1994 and 2025 (RARECAT 2025, GBIF 2026, NatureServe 2026, SEINet 2026).

Occurrences Comments

By applying a 1 km separation distance to herbarium specimens and NatureServe Network occurrence data documented between 1994 and 2025, it is estimated that there are nineteen occurrences rangewide (RARECAT 2025, GBIF 2026, NatureServe 2026, SEINet 2026). CNDDB (2026) estimates that there are 41 occurrences presumed extant, including 27 occurrences considered historic and last observed over 20 years ago.

Threat Impact Comments

The primary threats to this species are conversion of habitat and habitat fragmentation from residential and agricultural development (USFWS 2023, CNDDB 2026), since about 89% of extant occurrences are found on private lands where they receive little protection (USFWS 2007). Additional threats include competition with non-native plants (including Avena fatua, Brassica kaber, Bromus mollis, Bromus madritensis ssp. rubens, and Erodium circutarium), transmission line maintenance, recreational activities, mining, and road construction and maintenance (USFWS 2023, CNDDB 2026). While incompatible grazing practices were considered a threat at the time of listing, livestock grazing appears to be beneficial in reducing thatch from non-native grasses (USFWS 2023). A flood control project was also a past threat, with a new dam and wider spillway on Lake Success (USFWS 2007, USFWS 2023). Climate change is an emerging threat, with increasing duration of the dry season and an estimated 20% reduction in precipitation, which could lead to decreased seed germination of this annual species, likely decreasing its survival, reproduction, and genetic diversity, making this species extremely vulnerable to loss due to climate change (USFWS 2023).

Ecology & Habitat

Habitat

Pseudobahia peirsonii grows in valley and foothill grasslands, occasionally grassland-blue oak woodland community ecotones and openings of foothill (cismontane) woodlands in bare, dark, heavy adobe clay soils, which have high water retention properties and retain moisture into the summer dry season (FNA 2006, USFS 2023, CNPS 2026, Jepson Flora Project 2026). While it can be found in dense grass cover, it is most commonly found in sparsely vegetated areas with a mixture of grasses and other forbs. These grasslands are dominated by non-native grass species, and the composition of the prehistoric grassland communities is unknown.

Reproduction

This species flowers from March to May (FNA 2006).

Terrestrial Habitats

Forest/WoodlandWoodland - HardwoodSavannaGrassland/herbaceous

Other Nations (1)

United StatesN1

Province	Rank	Native
California	S1	Yes

Threat Assessments

Threat	Scope	Severity	Timing
1 - Residential & commercial development	Pervasive - large	Extreme - serious	High - moderate
1.1 - Housing & urban areas	Pervasive - large	Extreme - serious	High - moderate
2 - Agriculture & aquaculture	Large - restricted	Extreme - serious	High - moderate
2.1 - Annual & perennial non-timber crops	Restricted - small	Serious or 31-70% pop. decline	High - moderate
2.3 - Livestock farming & ranching	Large - restricted	Extreme - serious	High - moderate
3 - Energy production & mining	Small (1-10%)	Unknown	—
3.2 - Mining & quarrying	Small (1-10%)	Unknown	High - moderate
4 - Transportation & service corridors	Large - restricted	Moderate or 11-30% pop. decline	High - moderate
4.1 - Roads & railroads	Large - restricted	Moderate - slight	High - moderate
4.2 - Utility & service lines	Large - restricted	Moderate - slight	High - moderate
6 - Human intrusions & disturbance	Large - restricted	Serious - slight	High - moderate
6.1 - Recreational activities	Large - restricted	Serious - slight	High - moderate
7 - Natural system modifications	Large - restricted	Extreme - moderate	High - moderate
7.2 - Dams & water management/use	Large - restricted	Extreme - moderate	High - moderate
8 - Invasive & other problematic species, genes & diseases	Pervasive - large	Serious - moderate	High (continuing)
8.1 - Invasive non-native/alien species/diseases	Pervasive - large	Serious - moderate	High (continuing)
8.1.1 - Unspecified species	Pervasive - large	Serious - moderate	High (continuing)
11 - Climate change & severe weather	Pervasive (71-100%)	Serious - slight	High - low
11.2 - Droughts	Pervasive (71-100%)	Serious - slight	High - low

Plant Characteristics

DurationANNUAL

Economic Value (Genus)No

Roadless Areas (2)

California (2)

Area	Forest	Acres
Greenhorn Creek	Sequoia National Forest	28,226
Mill Creek	Sequoia National Forest	27,643

References (12)

California Native Plant Society (CNPS), Rare Plant Program. 2026. Inventory of Rare and Endangered Plants of California, online edition, v9.5. Online. Available: https://www.rareplants.cnps.org (accessed 2026).
California Natural Diversity Database (CNDDB). 2026. RareFind Version 5.3.0. California Department of Fish and Game, Sacramento.
Flora of North America Editorial Committee (FNA). 2006c. Flora of North America north of Mexico. Vol. 21. Magnoliophyta: Asteridae, part 8: Asteraceae, part 3. Oxford Univ. Press, New York. xxii + 616 pp.
Global Biodiversity Information Facility (GBIF). 2026. Global Biodiversity Information Facility (GBIF) data portal. Online. Available: https://www.gbif.org/ (accessed 2026).
Jepson Flora Project (eds.) 2026. Jepson eFlora. Online. Available: https://ucjeps.berkeley.edu/eflora/ (accessed 2026).
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
NatureServe. 2026. NatureServe Network Biodiversity Location Data. NatureServe, Arlington, Virginia.
NatureServe's Rapid Analysis of Rarity and Endangerment Conservation Assessment Tool (RARECAT). 2025. Version: 2.1.1 (released April 04, 2025).
Southwest Environmental Information Network (SEINet). 2026. Collections Databases. Online. Available: https://swbiodiversity.org/seinet/collections/index.php (accessed 2026).
U.S. Fish and Wildlife Service (USFWS). 1997. Determination of endangered status for Pseudobahia bahiifolia (Hartweg's golden sunburst) and threatened status for Pseudobahia peirsonii (San Joaquin adobe sunburst), two grassland plants from the Central Valley of California. Federal Register 62(25): 5542-5551.
U.S. Fish and Wildlife Service (USFWS). 2007. Pseudobahia bahiifolia (Hartweg's golden sunburst) and Pseudobahia peirsonii (San Joaquin adobe sunburst) 5-Year Review: Summary and Evaluation. U.S. Fish and Wildlife Service, Sacramento Fish and Wildlife Office, Sacramento, California. Online. Available: <http://ecos.fws.gov/docs/five_year_review/doc1869.pdf> (Accessed 2011).
U.S. Fish and Wildlife Service (USFWS). 2023. Pseudobahia bahiifolia (Hartweg's golden sunburst) and Pseudobahia peirsonii (San Joaquin adobe sunburst) 5-Year Review: Summary and Evaluation. U.S. Fish and Wildlife Service, Sacramento Fish and Wildlife Office, Sacramento, California. Online. Available: https://ecosphere-documents-production-public.s3.amazonaws.com/sams/public_docs/species_nonpublish/8922.pdf (Accessed 2026).

Pseudobahia peirsonii

Habitat

Reproduction

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