Taxon Report
Isoetes minima A. A. EatonColumbia quillwort |
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Taxon Summary
Isoetes minima, commonly known as Columbia quillwort, is a perennial cormiferous herb in the Isoetaceae that is found in California and elsewhere. It occurs within Meadows and seeps, growing at elevations from 2190 to 2190 meters. Isoetes minima is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.Classification
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Scientific Name: |
Isoetes minima A. A. Eaton |
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Common Name: |
Columbia quillwort |
| Family: | Isoetaceae |
| Element Code: | PPISO01081 |
| USDA Plants Symbol: | ISMI4 |
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Synonyms/Other Names: |
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Ecology and Life History
| Lifeform: | perennial cormiferous herb |
| Blooming Period: Jun | Jun |
| Elevation: | 2190-2190 (7185-7185) |
| General Habitats: | Meadows and seeps |
| Microhabitat: | Vernally Mesic |
| Microhabitat Details: |
Conservation Status
| CA Rare Plant Rank: | 1B.1 |
| Global Rank: | G1G2 |
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State Rank: |
S1 |
| State List: | None |
| Fed List: | None |
| Other Status: | BLM_S |
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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) | |
| Mt. Bidwell (4112082) | |
Threat List Data from the CNDDB
| Threat List Total: | 0 | |
| EOs with Threat Listed: | Total EOs | % of EOs |
| 0 | % | |
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Notes
| Field work needed (population size and extent, site quality and threats, vegetation and associated species, search for more occurrences). |
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Threats: |
| Possibly threatened by grazing and trampling. |
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Taxonomy: |
| Previously confused with I. howellii; mature female spores (megaspores) distinctive in being densely tuberculate and with a row of spinules along the equatorial ridge. |
Selected References
| Proposed Addition to California Rare Plant Rank 1B.1, G1G2 / S1 (2023) |
| Canadian Field-Naturalist 135: 293–304 (2021) |
| For first CA record see Madroño 67: 63–64 (2020) |
Citation
California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 15 December 2025].