Taxon Report

Riella americana M. Howe & Underw.

American riella

Print Report


Taxon Summary

Riella americana, commonly known as American riella, is a liverwort (aquatic) in the Riellaceae that is found in California and elsewhere. It occurs within Lower montane coniferous forest, and Pinyon and juniper woodland, growing at elevations from 1615 to 1615 meters. Riella americana is ranked 2B.2, Plants Rare, Threatened, or Endangered in California, But More Common Elsewhere; Moderately threatened in California.


  Classification

Scientific Name:
Riella americana M. Howe & Underw.
Common Name:
American riella
Family: Riellaceae
Element Code: NBHEP31020
USDA Plants Symbol: RIAM6
Synonyms/Other Names:

Ecology and Life History

Lifeform: liverwort (aquatic)
Blooming Period: Aug-Sep Aug-Sep
Elevation: 1615-1615 (5300-5300)
General Habitats: Lower montane coniferous forest, Pinyon and juniper woodland
Microhabitat:
Microhabitat Details: Arid and semiarid regions as a submerged aquatic in mud flats. In temporary pools and streams. Also in reservoirs and stock ponds.

Conservation Status

CA Rare Plant Rank: 2B.2
Global Rank: G2G3
State Rank:
S1
State List: None
Fed List: None
Other Status:
CRPR Changes:
  • changed from 2.2 to 2B.2 on 2013-06-12
  • added to 2.2 on 2011-03-23

Occurrence Data from the CNDDB

Total Occurrences: 1
Element Occurrence Ranks:
   Excellent (A) 0
   Good (B) 0
   Fair (C) 0
   Poor (D) 0
   None (X) 0
   Unknown (U) 1
California Endemic:  False
California Counties and Islands: Name (Code)
Modoc (MOD)
Quads: Name (Quad Code)
Big Sage Reservoir (4112056), Mahogany Ridge (4112055)

Notes

Similar to R. affinis.
Threats:
Taxonomy:

Selected References

Proposed New Add to Rank 2.2, G2? / S1?
Riella americana profile for potential Species of Conservation Concern evaluation (2018)
USFS Potential Species of Conservation Concern Profile
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].