Taxon Report
Castilleja densiflora (Benth.) T.I. Chuang & Heckard var. obispoensis (D.D. Keck) J.M. EggerSan Luis Obispo owl's-clover |
 © 2010 Aaron E. Sims |
Taxon Summary
Castilleja densiflora var. obispoensis, commonly known as San Luis Obispo owl's-clover, is a annual herb (hemiparasitic) in the Orobanchaceae that is found only in California. It occurs within Meadows and seeps, and Valley and foothill grassland, growing at elevations from 10 to 430 meters. Castilleja densiflora var. obispoensis is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.Classification
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Scientific Name: |
Castilleja densiflora (Benth.) T.I. Chuang & Heckard var. obispoensis (D.D. Keck) J.M. Egger |
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Common Name: |
San Luis Obispo owl's-clover |
| Family: | Orobanchaceae |
| Element Code: | PDSCR0D453 |
| USDA Plants Symbol: | |
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Synonyms/Other Names: |
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Ecology and Life History
| Lifeform: | annual herb (hemiparasitic) |
| Blooming Period: Mar-May | Mar-May |
| Elevation: | 10-430 (35-1410) |
| General Habitats: | Meadows and seeps, Valley and foothill grassland |
| Microhabitat: | Serpentine (sometimes) |
| Microhabitat Details: |
Conservation Status
| CA Rare Plant Rank: | 1B.2 |
| Global Rank: | G5T2 |
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State Rank: |
S2 |
| State List: | None |
| Fed List: | None |
| Other Status: | BLM_S; SB_SBBG |
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CRPR Changes: |
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Occurrence Data from the CNDDB
| Total Occurrences: | 69 |
| Element Occurrence Ranks: | |
| Excellent (A) | 5 |
| Good (B) | 12 |
| Fair (C) | 11 |
| Poor (D) | 3 |
| None (X) | 0 |
| Unknown (U) | 38 |
| California Endemic: True | |
| California Counties and Islands: Name (Code) | |
| San Luis Obispo (SLO) | |
| Quads: Name (Quad Code) | |
| Adelaida (3512067), Arroyo Grande NE (3512025), Bradley (3512077), Cambria (3512151), Cayucos (3512048), Lopez Mtn. (3512035), Morro Bay North (3512047), Morro Bay South (3512037), Oceano (3512015), Paso Robles (3512066), Pico Creek (3512152), Piedras Blancas (3512163), Pismo Beach (3512026), Port San Luis (3512027), San Luis Obispo (3512036), San Simeon (3512162), Santa Margarita (3512045) | |
Threat List Data from the CNDDB
| Threat List Total: | 14 | |
| EOs with Threat Listed: | Total EOs | % of EOs |
| 30 | 43 % | |
| Non-native plant impacts | 18 | 26% |
| Development | 12 | 17% |
| Grazing | 12 | 17% |
| Improper burning regime | 10 | 14% |
| Military operations | 9 | 13% |
| Feral pigs | 9 | 13% |
| Foot traffic/trampling | 3 | 4% |
| Erosion/runoff | 3 | 4% |
| Wood cutting or brush clearing | 3 | 4% |
| Recreational use (non-ORV) | 2 | 2% |
| Road/trail construction/maint. | 2 | 2% |
| Other | 1 | 1% |
| Biocides | 1 | 1% |
| Hybridization | 1 | 1% |
Notes
| Threatened by development and grazing. See C. densiflora ssp. obispoensis in TJM 2. See Proceedings of the California Academy of Sciences IV 16:539 (1927) for original description, and Systematic Botany 16:656 (1991) and Phytologia 90(1):63-81 (2008) for revised nomenclature. |
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Threats: |
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Taxonomy: |
Citation
California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 28 April 2025].