Taxon Report

Plagiobothrys glaber (Gray) Jtn.

hairless popcornflower

Print Report


Taxon Summary

Plagiobothrys glaber, commonly known as hairless popcornflower, is a annual herb in the Boraginaceae that is found only in California. It occurs within Marshes and swamps (coastal salt), and Meadows and seeps (alkaline), growing at elevations from 15 to 180 meters. Plagiobothrys glaber is ranked 1A, Plants Presumed Extirpated in California and Either Rare or Extinct Elsewhere.

  Classification
Scientific Name:
 Plagiobothrys glaber (Gray) Jtn.
Common Name:
 hairless popcornflower
Family: Boraginaceae
Element Code: PDBOR0V0B0
USDA Plants Symbol: PLGL
Synonyms/Other Names:

Ecology and Life History
Lifeform: annual herb
Blooming Period: Mar-May Mar-May
Elevation: 15-180 (50-590)
General Habitats: Marshes and swamps, Meadows and seeps
Microhabitat:
Microhabitat Details:

Conservation Status
CA Rare Plant Rank: 1A
Global Rank: GX
State Rank:
 SX
State List: None
Fed List: None
Other Status:
CRPR Changes:

Occurrence Data from the CNDDB
Total Occurrences: 9
Element Occurrence Ranks:
   Excellent (A) 0
   Good (B) 0
   Fair (C) 0
   Poor (D) 0
   None (X) 9
   Unknown (U) 0

Location
California Endemic:  True
California Counties and Islands: Name (Code)
Alameda (ALA)*, Marin (MRN)*, San Benito (SBT)*, Santa Clara (SCL)*
Quads: Name (Quad Code)
Altamont (3712166)*, Hayward (3712261)*, Livermore (3712167), Los Gatos (3712128)*, Newark (3712251)*, Point Bonita (3712275), San Felipe (3612184)*, San Francisco North (3712274), San Jose East (3712137)*, San Jose West (3712138)*, San Quentin (3712284), San Rafael (3712285)*

Threat List Data from the CNDDB

Threat List Total: 2
EOs with Threat Listed: Total EOs % of EOs
9 100 %
Development 8 88%
Agriculture 1 11%

Notes
Last confirmed sighting in 1954. Possibly relocated near Antioch; identification uncertain. All collections since 1930's located in the Hollister area; plant should also be looked for there. Possibly a variety of P. stipitatus. See Proceedings of the American Academy of Arts and Sciences 17:227 (1882) for original description.
Threats:
Taxonomy:

Selected References

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 5 November 2025].