Taxon Report

Catabrosa aquatica (L.) P. Beauv.

water whorlgrass

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Taxon Summary

Catabrosa aquatica, commonly known as water whorlgrass, is a perennial stoloniferous herb in the Poaceae that is found in California and elsewhere. It occurs within Meadows and seeps, growing at elevations from to meters. Catabrosa aquatica is ranked 2B.1, Plants Rare, Threatened, or Endangered in California, But More Common Elsewhere; Seriously threatened in California.


  Classification

Scientific Name:
Catabrosa aquatica (L.) P. Beauv.
Common Name:
water whorlgrass
Family: Poaceae
Element Code: PMPOA19010
USDA Plants Symbol:
Synonyms/Other Names:

Ecology and Life History

Lifeform: perennial stoloniferous herb
Blooming Period: Jul-Sep Jul-Sep
Elevation: - (-)
General Habitats: Meadows and seeps
Microhabitat: Streambanks
Microhabitat Details: Sometimes stoloniferous or rhizomatous.

Occurrence Data from the CNDDB

Total Occurrences: 1
Element Occurrence Ranks:
   Excellent (A) 0
   Good (B) 1
   Fair (C) 0
   Poor (D) 0
   None (X) 0
   Unknown (U) 0
California Endemic:  False
California Counties and Islands: Name (Code)
Siskiyou (SIS)
Quads: Name (Quad Code)
Panther Rock (4112272)

Threat List Data from the CNDDB

Threat List Total: 3
EOs with Threat Listed: Total EOs % of EOs
1 100 %
Foot traffic/trampling 1 100%
Grazing 1 100%
ORV activity 1 100%

Notes

Discovered in CA by Marla Knight in 2007.  Similar to Torreyochloa pallida var. pauciflora; differs in having leaf sheaths closed at least part of the way, vs. leaf sheaths open (with overlapping margins) to the base in T. pallidaSee Species Plantarum 1: 64 (1753) for original description, and Essai d'une Nouvelle Agrostographie 97 (1812) for revised nomenclature.
Threats:
Possibly threatened by grazing, trampling, vehicles, and recreational activities.
Taxonomy:

Selected References

Proposed Addition to CRPR 2B.1, G5 / S1 (2018)
Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 27 January 2025].