| | 1. Fruit 2–3 mm, nut-like, indehiscent, 1–2-seeded |
| C. heterandra |
| | 1' Fruit > 5 mm, not nut-like, dehiscent, many-seeded |
| |
| | 2. Petal blade lobed above |
| |
| | 3. Stamens 4; hypanthium slender, > 10 mm |
| |
| | 4. Petal length ± = width, outer lobes wider than middle |
| C. breweri |
| | 4' Petal length ± 2 × width, lobes ± equally wide |
| C. concinna |
| | 5. Stigma beyond anthers; petals 15–30 mm |
| subsp. concinna |
| | 5' Stigma not beyond anthers; petals 10–20 mm |
| |
| | 6. Petal lobes prominent, separated by deep sinuses |
| subsp. automixa |
| | 6' Petal lobes short, not separated by deep sinuses |
| subsp. raichei |
| | 3' Stamens 8; hypanthium not slender, < 7 mm |
| |
| | 7. Petal lobes 2, a tooth between |
| C. xantiana |
| | 8. Petals 6–12 mm; stigma not beyond anthers |
| subsp. parviflora |
| | 8' Petals 12–20 mm; stigma beyond anthers |
| subsp. xantiana |
| | 7' Petal lobes 2, no tooth between |
| C. biloba |
| | 9. Petals bright pink to magenta, length generally > 1.5 × width |
| subsp. australis |
| | 9' Petals lavender to pink or purplish pink, length generally not > 1.5 × width |
| |
| | 10. Petal lobes generally 1/5–1/2 petal |
| subsp. biloba |
| | 10' Petal lobes generally < 1/5 petal |
| C. biloba subsp. brandegeeae |
| | 2' Petal blade not or inconspicuously lobed above (see also C. biloba subsp. brandegeae) |
| |
| | 11. Petal claw 2-lobed or -toothed, not entire |
| |
| | 12. Petals 6–14 mm; stigma not beyond anthers |
| |
| | 13. Petal generally spotted, blade unlobed above |
| C. rhomboidea |
| | 13' Petal unspotted, blade inconspicuously 3-lobed above |
| C. stellata |
| | 12' Petals generally > 12 mm; stigma beyond anthers |
| |
| | 14. Inflorescence axis in bud recurved < 3 nodes above open flowers; petal length 1.4–1.6 × width |
| C. mildrediae |
| | 14' Inflorescence axis in bud straight 4 or more nodes above open flowers, recurved at tip; petal length 1.6–3 × width |
| |
| | 15. Flower bud fusiform, tip acute |
| C. borealis |
| | 16. Seed 1.8–2.5 mm; Cascade Range Foothills |
| subsp. arida |
| | 16' Seed 1.5–1.8 mm; Klamath Ranges |
| subsp. borealis |
| | 15' Flower bud obovate, tip obtuse |
| |
| | 17. Petal length 1.6–2 × width — Butte Co. |
| C. mosquinii |
| | 18. Leaf elliptic to ovate |
| C. mosquinii |
| | 18' Leaf linear-lanceolate |
| C. mosquinii |
| | 17' Petal length 1.9–3 × width |
| |
| | 19. Leaf linear-lanceolate |
| C. australis |
| | 19' Leaf elliptic to ovate |
| C. virgata |
| | 11' Petal claw ± 0 or entire |
| |
| | 20. Inflorescence axis in bud recurved at tip, in flower ± straight; buds pendent |
| |
| | 21. Petals white to pale cream, not darker-flecked or -spotted, fading pink, generally < 10 mm |
| C. epilobioides |
| | 21' Petals darker than white to pale cream, at least on margin, or darker-flecked or -spotted, generally > 10 mm |
| |
| | 22. Anthers alike, tips acute or slender; pollen yellow to ± white |
| |
| | 23. Ovary, immature fruit 8-grooved; fruit not wider above |
| |
| | 24. Ovary hairs ± sparse; pedicel 5–15 mm |
| C. arcuata |
| | 24' Ovary hairs dense; pedicel < 3 mm |
| C. lassenensis |
| | 23' Ovary, immature fruit 4-, rarely 8-grooved; fruit generally wider above |
| C. gracilis |
| | 25. Petals 6–23 mm, spot 0, base darker or not; stigma not beyond anthers |
| subsp. gracilis |
| | 25' Petals 20–40 mm, with a red spot near middle or red at base; stigma beyond anthers |
| |
| | 26. Petals with a red spot near middle |
| subsp. sonomensis |
| |
| | 27. Petals generally 3–4 cm; s Cascade Range Foothills |
| subsp. albicaulis |
| | 27' Petals generally 2–3 cm; Inner North Coast Ranges |
| subsp. tracyi |
| | 22' Anthers in 2 unlike series, obtuse at tip, inner generally << outer; inner pollen generally cream, outer generally blue-gray or lavender |
| |
| | 28. Petals 6–12 mm; stigma not beyond anthers |
| |
| | 29. Petals pink, generally darker-flecked |
| C. modesta |
| | 29' Petals pale pink shading to ± white near base, purple-flecked |
| C. similis |
| | 28' Petals 10–35 mm; stigma beyond anthers |
| |
| | 30. Petals oblanceolate; corolla rotate |
| C. lingulata |
| | 30' Petals fan-shaped; corolla bowl-shaped |
| |
| | 31. Ovary, immature fruit 8-grooved; petals generally white-streaked |
| C. dudleyana |
| | 31' Ovary, immature fruit 4-grooved; petals darker near tip, shading to white near middle, with a darker line or zone near base |
| |
| | 32. Width of outer filaments ± 2 × inner; ring of hairs in hypanthium below tip |
| C. cylindrica |
| | 33. Ovary, fruit wider above |
| subsp. clavicarpa |
| | 33' Ovary, fruit cylindric |
| subsp. cylindrica |
| | 32' Width of all filaments ± equal; ring of hairs in hypanthium ± at tip |
| |
| | 34. Fruit beak < 3 mm or 0 |
| C. lewisii |
| C. rostrata |
| | 20' Inflorescence axis in bud generally ± straight; buds erect or reflexed |
| |
| |
| | 36. Corolla bowl-shaped; petals ± not clawed |
| |
| | 37. Seeds brown; not Monterey Co. |
| C. bottae |
| | 37' Seeds gray; n Outer South Coast Ranges (Monterey Co.) |
| C. jolonensis |
| | 36' Corolla rotate; petals clawed |
| |
| C. delicata |
| | 38' Petal claw = or > blade |
| |
| | 39. Calyx, ovary sparsely to densely puberulent and with longer, straight, spreading hairs < 3 mm |
| C. unguiculata |
| | 39' Calyx, ovary sparsely to densely puberulent without longer, straight, spreading hairs < 3 mm |
| |
| | 40. Leaf not glaucous, bright green |
| C. exilis |
| | 40' Leaf glaucous, gray-green or reddish |
| |
| | 41. Sepals generally dark red-purple; stigma beyond anthers |
| C. springvillensis |
| | 41' Sepals green, red-tinged or not; stigma beyond anthers or not |
| C. tembloriensis |
| | 42. Petals ± 10 mm wide; stigma not beyond anthers |
| subsp. calientensis |
| | 42' Petals generally < 10 mm wide; stigma beyond anthers or not |
| subsp. tembloriensis |
| |
| | 43. Ovary, immature fruit 4-grooved |
| |
| | 44. Petals with a ± red spot or zone at base |
| |
| | 45. Petals 10–30 mm; stigma beyond anthers |
| C. rubicunda |
| | 45' Petals 5–13 mm; stigma not beyond anthers |
| C. franciscana |
| | 44' Petals with a red spot or marks near middle |
| C. amoena |
| | 46. Stem decumbent; inflorescence internode generally < subtending flower |
| subsp. amoena |
| | 46' Stem erect; inflorescence internode generally > subtending flower |
| subsp. huntiana |
| | 43' Ovary, immature fruit 8-grooved |
| |
| | 47. Stigma not beyond anthers; petals generally 5–15 mm |
| |
| | 48. Stem decumbent to prostrate; leaf oblanceolate, elliptic, or obovate, tip generally obtuse |
| |
| | 49. Petal 5–11 mm, spot 0 |
| C. davyi |
| | 49' Petal 10–15 mm, spot reddish, above base |
| C. prostrata |
| | 48' Stem erect; leaf linear to ovate, tip generally acute |
| |
| | 50. Immature fruit length > 9 × width; sepals staying fused in 4's |
| C. affinis |
| | 50' Immature fruit length < 8 × width; sepals staying fused in 2's or all coming free |
| C. purpurea subsp. quadrivulnera |
| | 47' Stigma generally beyond anthers; petals 10–60 mm |
| |
| | 51. Ovary, immature fruit fusiform, grooves 8, 4 deeper |
| C. amoena subsp. whitneyi |
| | 51' Ovary, immature fruit generally ± cylindric, grooves 8, equal |
| |
| | 52. Petals ± without a red or purple spot |
| |
| | 53. Petals dark reddish purple |
| |
| | 54. Sepals fused to tip in bud |
| 2 C. speciosa subsp. speciosa |
| | 54' Sepals free at tip in bud |
| 2 C. williamsonii |
| | 53' Petals pink or lavender to purple or purplish red, below often cream or lighter |
| |
| | 55. Inflorescence open; leaf linear to narrow-lanceolate |
| C. speciosa subsp. immaculata |
| | 55' Inflorescence dense; leaf wide-lanceolate to elliptic or ovate |
| 2 C. purpurea subsp. purpurea |
| | 52' Petals generally with a red or purple spot |
| |
| | 56. Petal spot near middle or below |
| |
| | 57. Inflorescence dense; ovary generally > internode above |
| C. speciosa subsp. nitens |
| | 57' Inflorescence open; ovary generally < internode above |
| C. speciosa |
| | 58. Branches on well developed plants few, many-flowered |
| subsp. polyantha |
| | 58' Branches on well developed plants many, few-flowered |
| subsp. speciosa |
| | 56' Petal spot above middle |
| |
| | 59. Leaf lanceolate to elliptic or ovate, length generally < 5 × width; inflorescence dense |
| |
| | 60. Hypanthium 10–15 mm, veined; petals 20–25 mm |
| C. imbricata |
| | 60' Hypanthium 2–10 mm, ± not veined; petals 10–25 mm |
| 2 C. purpurea subsp. purpurea |
| | 59' Leaf linear to narrow-lanceolate, length > 5 × width; inflorescence open |
| |
| | 61. Sepals fused to tip in bud |
| C. purpurea subsp. viminea |
| | 61' Sepals free at tip in bud |
| 2 C. williamsonii
|