Taxon Report
Crocanthemum greenei (B.L. Rob.) Sorrieisland rush-rose |
 © 2003 Keir Morse |
Taxon Summary
Crocanthemum greenei, commonly known as island rush-rose, is a perennial evergreen shrub in the Cistaceae that is found only in California. It occurs within Chaparral, Cismontane woodland, Closed-cone coniferous forest, and Coastal scrub, growing at elevations from 15 to 490 meters. Crocanthemum greenei is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.Classification
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Scientific Name: |
Crocanthemum greenei (B.L. Rob.) Sorrie |
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Common Name: |
island rush-rose |
| Family: | Cistaceae |
| Element Code: | PDCIS02090 |
| USDA Plants Symbol: | |
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Synonyms/Other Names: |
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Ecology and Life History
| Lifeform: | perennial evergreen shrub |
| Blooming Period: (Jan)Mar-Jul(Aug) | (Jan)Mar-Jul(Aug) |
| Elevation: | 15-490 (50-1610) |
| General Habitats: | Chaparral, Cismontane woodland, Closed-cone coniferous forest, Coastal scrub |
| Microhabitat: | Openings, Rocky |
| Microhabitat Details: |
Conservation Status
| CA Rare Plant Rank: | 1B.2 |
| Global Rank: | G3 |
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State Rank: |
S3 |
| State List: | None |
| Fed List: | FT |
| Other Status: | |
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CRPR Changes: |
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Occurrence Data from the CNDDB
| Total Occurrences: | 66 |
| Element Occurrence Ranks: | |
| Excellent (A) | 1 |
| Good (B) | 16 |
| Fair (C) | 7 |
| Poor (D) | 2 |
| None (X) | 1 |
| Unknown (U) | 39 |
| California Endemic: True | |
| California Counties and Islands: Name (Code) | |
| Los Angeles (LAX), Santa Barbara (SBA) | |
| Quads: Name (Quad Code) | |
| San Miguel Island East (3312083), San Miguel Island West (3312084)*, Santa Catalina East (3311833), Santa Catalina North (3311844), Santa Catalina South (3311834), Santa Catalina West (3311845), Santa Cruz Island A (3311987), Santa Cruz Island B (3311986), Santa Cruz Island C (3311985), Santa Cruz Island D (3311984), Santa Rosa Island East (3311988), Santa Rosa Island North (3312081), Santa Rosa Island South (3312071) | |
Threat List Data from the CNDDB
| Threat List Total: | 8 | |
| EOs with Threat Listed: | Total EOs | % of EOs |
| 15 | 23 % | |
| Grazing | 8 | 12% |
| Non-native animal impacts | 8 | 12% |
| Foot traffic/trampling | 7 | 10% |
| Erosion/runoff | 5 | 7% |
| Non-native plant impacts | 4 | 6% |
| Over-collecting/poaching | 3 | 4% |
| Road/trail construction/maint. | 2 | 3% |
| Other | 1 | 1% |
Notes
| Six occurrences were discovered between 1999 and 2006 on SRO Isl., where it had not been collected since the 1930s. Increasing in abundance on SCZ Isl. and SRO Isl. after removal of feral herbivores; also increasing on SCT Isl. where non-native deer still present. Presumed extirpated on SMI Isl., where it was last collected in 1939; recent surveys unsuccessful. |
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Threats: |
| Threatened by altered fire regimes and non-native plants. Possibly threatened by erosion. Threatened by herbivory from non-native deer on SCT Isl. Hybridizes with H. scoparium. |
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Taxonomy: |
Selected References
| Bulletin of the California Academy of Sciences 2(6B): 144 (1886) |
| Phytologia 93(2): 270 (2011) |
Citation
California Native Plant Society, Rare Plant Program. 2026. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 28 May 2026].