| 1. Leaf ± 5-lobed shrub, large-flowered, unarmed; fruit finely hairy |
| R. parviflorus |
| 1' Leaf, generally 3-lobed or compound, sometimes ± unlobed |
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| 2. Main stems 5-angled, stout; leaflets 5 on large leaves; flowers often > 10; escaped from cultivated prickles generally wide-based, ± curved (0) |
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| 3. Leaflets deeply lobed or again compound inflorescence ± panicle |
| R. laciniatus |
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| 4. Inflorescence a raceme (bracts often leaf-like); leaflets generally widest below middle, green below; sepal tips 18 mm |
| P. pensilvanicus |
| 4' Inflorescence a panicle; leaflets generally widest above middle, white below; sepal tips generally ± 1 mm |
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| R. discolor |
| R. ulmifolius var. inermis |
| 2' Main stems round, slender to stout; leaflets seldom > 3; flowers generally 110 native |
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| 6. Plant ± prostrate; pistils 515; prickles often 0 fruit puberulent; > 750 m |
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| 7. Stipules linear; leaf compound, white below; stem not rooting at nodes prickly |
| 2 R. glaucifolius |
| 7' Stipules ± ovate; leaf often simple, green below; stem rooting at nodes Klamath Ranges, High North Coast Ranges |
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| 8. Prickles 0; petals white |
| R. lasiococcus |
| 8' Prickly; petals generally dull purple to pink (white) |
| R. nivalis |
| 6' Plant decumbent to erect; pistils generally > 10; prickles generally present |
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| 9. Leaf green below; < 1500 m |
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| 10. Mains stems erect; petals ± red; fruit yellow to red; flower bisexual; nw California |
| R. spectabilis |
| 10' Main stems clambering; petals white; fruit black; flowers generally unisexual; common, California Floristic Province |
| R. ursinus |
| 9' Leaf white below; < 2400 m |
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| 11. Plant prostrate to decumbent; stem 23 mm diam; pistils < 10; inflorescence prickles few, ± slender, straight |
| 2 R. glaucifolius |
| 11' Plant arched to erect, stem 410 mm diam; pistils generally > 15; inflorescence prickles many, generally ± wide-based, generally curved |
| R. leucodermis
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