| 1. Nodal spines 0 (subg. Coreosma) |
| |
| 2. Hypanthium disk- or saucer-shaped, barely exceeding ovary |
| |
| 3. Leaves evergreen, lobes 0 or very shallow; Peninsular Ranges, s Channel Islands (Santa Catalina Island) |
| R. viburnifolium |
| 3' Leaves deciduous, lobes deep; mainland |
| |
| 4. Ovary and leaf blade lower side with stalked glands; stem spreading or decumbent |
| R. laxiflorum |
| 4' Ovary and leaf blade lower side with sessile glands; stem ± erect |
| |
| 5. Sepals green; North Coast, w Klamath Ranges, Outer North Coast Ranges |
| R. bracteosum |
| 5' Sepals white; n Modoc Plateau |
| R. hudsonianum var. petiolare |
| 2' Hypanthium cup- to tube-shaped, clearly exceeding ovary |
| |
| R. aureum |
| 7. Flower odor spicy; petals yellow turning orange; sepals 58 mm |
| var. aureum |
| 7' Flower odor 0; petals yellow turning deep red; sepals 34 mm |
| var. gracillimum |
| 6' Sepals white or whitish green to pink, red, or purple |
| |
| 8. Anther tip with cup-like depression |
| |
| 9. Hypanthium < 2 × longer than wide; stamens inserted at level of petals; fruit black to glaucous |
| R. viscosissimum |
| 9' Hypanthium > 2 × longer than wide; stamens inserted below level of petals; fruit red |
| R. cereum |
| 10. Bract tip wide, with several prominent teeth; styles generally hairy |
| var. cereum |
| 10' Bract tip acute, with 13 shallow teeth on each side; styles glabrous |
| var. inebrians |
| 8' Anther tip rounded, blunt, or shallowly notched |
| |
| 11. Styles glabrous at base |
| |
| 12. Sepals erect; hypanthium ± as long as wide |
| R. nevadense |
| 12' Sepals spreading; hypanthium longer than wide |
| R. sanguineum |
| 13. Inflorescence pendent; sepals pink to white |
| var. glutinosum |
| 13' Inflorescence erect to spreading; sepals red |
| var. sanguineum |
| 11' Styles hairy, at least at base |
| |
| 14. Hypanthium wider than long; styles free to base; inflorescence dense, many-flowered, spike- or head-like |
| R. canthariforme |
| 14' Hypanthium ± longer than wide; styles fused at least in basal 1/2; inflorescence open |
| |
| 15. Hypanthium white, barely longer than wide |
| R. indecorum |
| 15' Hypanthium pink, ± 2 × longer than wide |
| R. malvaceum |
| 16. Leaf blade upper surface dull olive-green |
| var. malvaceum |
| 16' Leaf blade upper surface bright green |
| var. viridifolium |
| 1' Nodal spines present (sometimes 0 on some shoots) |
| |
| 17. Inflorescence generally > 5-flowered; hypanthium disk- or saucer-shaped; pedicel jointed to ovary (subg. Grossularioides) |
| |
| 18. Leaf hairs 0 or sparse, nonglandular; fruit black |
| R. lacustre |
| 18' Leaf hairy, glandular; fruit orange-red |
| R. montigenum |
| 17' Inflorescence < 5-flowered; hypanthium cup- to tube-shaped; pedicel not jointed to ovary (subg. Grossularia) |
| |
| R. speciosum |
| 19' Sepals 5, spreading or reflexed |
| |
| 20. Anthers not exserted from petals |
| |
| 21. Stem low, spreading; internode bristles glandular |
| R. tularense |
| 21' Stem erect or arched; internode bristles 0 |
| |
| 22. Ovary hairs conspicuous, short and long, glandular and not |
| R. velutinum |
| 22' Ovary hairs generally 0 or inconspicuous, generally short, generally nonglandular |
| |
| 23. Hypanthium > 3 mm; 21003100 m |
| R. lasianthum |
| 23' Hypanthium < 3 mm; < 1350 m |
| R. quercetorum |
| 20' Anthers exserted from petals |
| |
| 24. Styles hairy at least at base |
| |
| 25. Calyx purple or purple-green; filaments exceeding petals by < 2 mm |
| R. divaricatum |
| 26. Petals pink or red; styles 811 mm |
| var. parishii |
| 26' Petals white; styles 58 mm |
| var. pubiflorum |
| 25' Calyx greenish white, purple at base or not; filaments exceeding petals by > 3 mm |
| R. inerme |
| 27. Leaf hairs 0 to sparse, short, soft; sepal hairs 0 |
| var. inerme |
| 27' Leaf hairs sparse to dense, long, soft to stiff; sepal hairs soft |
| var. klamathense |
| 24' Styles glabrous at base |
| |
| 28. Petals bright yellow, outer surface deeply concave, tip hooded |
| R. marshallii |
| 28' Petals white to pink, flat or outer surface shallowly concave or margins curled inward, sometimes nearly touching, tip not hooded |
| |
| 29. Petals flat or outer surface shallowly concave; stem low, spreading |
| R. binominatum |
| 29' Petal margins curled inward, sometimes nearly touching; stem ± erect |
| |
| 30. Anthers oblong, tips blunt or rounded; styles ± not exceeding anthers |
| |
| 31. Anthers slightly longer than wide when dehisced, with sessile glands on back; internodal bristles 0 |
| R. lobbii |
| 31' Anthers much longer than wide when dehisced, glabrous; internodal bristles present |
| R. sericeum |
| 30' Anthers lanceolate to ovate, tips acute or with a point; styles exceeding anthers |
| |
| 32. Leaf blade lower surface glandular |
| |
| 33. Internodal bristles 0; hypanthium longer than wide |
| R. amarum |
| 33' Internodal bristles present; hypanthium generally ± as long as wide |
| |
| 34. Sepals purple; fruit purple |
| R. menziesii |
| 34' Sepals greenish white; fruit yellow |
| R. victoris |
| 32' Leaf blade lower surface nonglandular |
| |
| 35. Hypanthium ± as long as wide |
| R. californicum |
| 36. Leaf hairs 0 or sparse; stamens > 2 × petals |
| var. californicum |
| 36' Leaf hairy; stamens ± = to barely > petals |
| var. hesperium |
| 35' Hypanthium longer than wide |
| |
| 37. Sepals pinkish, spreading; n Channel Islands (Santa Cruz Island) |
| R. thacherianum |
| 37' Sepals purple, reflexed; mainland |
| R. roezlii |
| 38. Leaf blade lower surface and hypanthium glabrous |
| var. cruentum |
| 38' Leaf blade lower surface and hypanthium hairy or densely white-hairy |
| |
| 39. Hypanthium and leaf blade lower surface densely white-hairy |
| var. amictum |
| 39' Hypanthium and leaf blade lower surface hairy |
| var. roezlii
|