| 1. Leaflets << 1 cm, toothed 1/2 to base; hypanthium densely prickly rare Peninsular Ranges |
| R. minutifolia |
| 1' Leaflets > 1 cm, toothed < 1/4 to base; hypanthium glabrous to stalked-glandular |
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| 2. Sepal with toothed lateral lobes; stem generally ± olive-green; prickles compressed side-to-side, curved; alien |
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| 3. Leaves and sepals glandless; terminal leaflet ± ovate |
| R. canina |
| 3' Leaves and sepals glandular; terminal leaflet generally elliptic to ± widely obovate |
| R. eglanteria |
| 2' Sepal body generally entire (tip sometimes toothed); stem generally ± grayish or brownish; prickles compressed or slender, not curved (except R. californica); native |
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| 4. Sepals deciduous in fruit; hypanthium generally 23 mm wide at flowering; pistils < 10; sepal tip generally << body; petals ± 10 mm leaflets glabrous, flowers 13 |
| R. gymnocarpa |
| 4' Sepals persistent; hypanthium generally 37 mm wide at flowering; pistils generally > 10 (except some R. bridgesii); sepal tip often > body; petals generally 1025 mm |
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| 5. Dwarf ± rhizomatous shrubs generally 110 dm; leaflet tip often ± truncate leaf margins generally ± glandular, double-toothed |
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| 6. Hypanthium stalked-glandular prickles generally ± slender, often many; flowers generally 25; Northwestern California, Central Western California, 1501550 m |
| R. spithamea |
| 6' Hypanthium generally glabrous |
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| 7. Prickles few, base thick; terminal leaflet generally widely obovate; flower 1(5); Cascade Range, Sierra Nevada, 9002500 m |
| R. bridgesii |
| 7' Prickles generally many, both slender and base thick; terminal leaflet generally ± elliptic; flowers generally 15; Central Western California, generally < 300 m |
| R. pinetorum |
| 5' Open or thicket-forming shrubs generally > 5 dm; leaflet tip not truncate |
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| 8. Prickles generally ± slender, ± straight, fewmany; leaves and sepals glandless; flowers 15(10); Cascade Range, High Sierra Nevada, San Gabriel Mountains, San Bernardino Mountains, Great Basin Floristic Province, Desert Mountains |
| R. woodsii var. ultramontana |
| 8' Prickles generally ± thick-based, often curved, generally ± few (except R. nutkana); leaves and sepals often glandular; flowers often > 5; California Floristic Province (except High Sierra Nevada) |
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| 9. Prickles generally curved, not contrasting with stem; sepals often glandless, tip generally ± = body; pedicel generally ± hairy |
| R. californica |
| 9' Prickles ± straight, generally whitish, contrasting with dark stem; sepals generally ± glandular, tip generally > body; pedicel glabrous to glandular, generally not hairy |
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| 10. Flower generally 1(4); sepal tip generally toothed; leaf ± glandular; hypanthium generally 57 mm wide at flowering; pedicel sometimes glandular; petals generally 1825 mm; w Northwestern California; < 700 m |
| R. nutkana var. nutkana |
| 10' Flowers generally 210; sepal tip entire; leaf glandless; hypanthium generally 36 mm wide at flowering; pedicel generally glabrous; petals ± 1520 mm; Northwestern California, Cascade Range; < 2100 m |
| R. pisocarpa
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