Taxon Report
Riella americana M. Howe & Underw.American riella |
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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
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Scientific Name: |
Riella americana M. Howe & Underw. |
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Common Name: |
American riella |
| Family: | Riellaceae |
| Element Code: | NBHEP31020 |
| USDA Plants Symbol: | RIAM6 |
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Synonyms/Other Names: |
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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 |
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State Rank: |
S1 |
| State List: | None |
| Fed List: | None |
| Other Status: | |
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CRPR Changes: |
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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) | |
Threat List Data from the CNDDB
| Threat List Total: | 0 | |
| EOs with Threat Listed: | Total EOs | % of EOs |
| 0 | % | |
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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 24 October 2025].