Taxon Report
Calamagrostis crassiglumis Thurb.Thurber's reed grass |
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Taxon Summary
Calamagrostis crassiglumis, commonly known as Thurber's reed grass, is a perennial rhizomatous herb in the Poaceae that is found in California and elsewhere. It occurs within Coastal scrub (mesic), and Marshes and swamps (freshwater), growing at elevations from 10 to 60 meters. Calamagrostis crassiglumis is ranked 2B.1, Plants Rare, Threatened, or Endangered in California, But More Common Elsewhere; Seriously threatened in California.Classification
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Scientific Name: |
Calamagrostis crassiglumis Thurb. |
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Common Name: |
Thurber's reed grass |
| Family: | Poaceae |
| Element Code: | PMPOA17070 |
| USDA Plants Symbol: | |
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Synonyms/Other Names: |
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Ecology and Life History
| Lifeform: | perennial rhizomatous herb |
| Blooming Period: May-Aug | May-Aug |
| Elevation: | 10-60 (35-195) |
| General Habitats: | Coastal scrub, Marshes and swamps |
| Microhabitat: | |
| Microhabitat Details: |
Conservation Status
| CA Rare Plant Rank: | 2B.1 |
| Global Rank: | G5Q |
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State Rank: |
S2 |
| 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: | 15 |
| Element Occurrence Ranks: | |
| Excellent (A) | 1 |
| Good (B) | 2 |
| Fair (C) | 2 |
| Poor (D) | 0 |
| None (X) | 0 |
| Unknown (U) | 10 |
| California Endemic: False | |
| California Counties and Islands: Name (Code) | |
| Del Norte (DNT), Humboldt (HUM), Marin (MRN), Mendocino (MEN), Sonoma (SON) | |
| Quads: Name (Quad Code) | |
| Ah Pah Ridge (4112348), Bodega Head (3812331), Crescent City (4112472), Drakes Bay (3812218), Fern Canyon (4112441), High Divide (4112481), High Plateau Mtn. (4112388), Holter Ridge (4112338), Inglenook (3912357), Mendocino (3912337), Orick (4112431), San Rafael (3712285), Sebastopol (3812247), Sister Rocks (4112462) | |
Threat List Data from the CNDDB
| Threat List Total: | 4 | |
| EOs with Threat Listed: | Total EOs | % of EOs |
| 5 | 33 % | |
| Grazing | 5 | 33% |
| Non-native plant impacts | 1 | 6% |
| Road/trail construction/maint. | 1 | 6% |
| Foot traffic/trampling | 1 | 6% |
Notes
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Threats: |
| Threatened by grazing at Pt. Reyes NS. |
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Taxonomy: |
| A synonym of C. stricta ssp. inexpansa in TJM (1993) and TJM 2; distinguished from this taxon in glume texture and shape: C. crassiglumis has thickened glumes that are rounded towards the base (vs. membranous, not thickened glumes that are keeled towards the base), generally shorter ligules (1-3 mm long vs. 2-5.5(6) mm long), and generally shorter panicles (3-8 cm long vs. (5)8-15 cm long in C. stricta ssp. inexpansa). |
Selected References
| Proposed retention at current rank 2.1 (2013) |
| Proposed Change from CRPR 2B.1 to 3.1, Retention as G3Q / S2? (2013) |
| Botany of California 2:281 (1880) |
| Calamagrostis crassiglumis profile for potential Species of Conservation Concern evaluation (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].