| 1. Stipule leaf-like, ± = leaf, pinnately lobed; generally annual; alien |
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| 2. Petals generally < sepals, mostly cream, sometimes with some blue-violet on upper 4, spur ± = sepal appendages |
| V. arvensis |
| 2' Petals generally > sepals, mainly blue-violet (rarely yellow), spur > sepal appendages sometimes per |
| V. tricolor |
| 1' Stipule not leaf-like, << leaf, entire or toothed; perennial herb; generally native |
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| 3. Leaf dissected to compound |
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| 4. Cleistogamous flowers present, sometimes exclusively; leaf blade generally wider than long |
| V. sheltonii |
| 4' Cleistogamous flowers 0; leaf blade generally longer than wide |
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| 5. Upper 2 petals golden-yellow on front, brown to very dark on back |
| V. douglasii |
| 5' Upper 2 petals dark red-violet |
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| 6. Lower 3 petals bluish to white, bases with yellow area; stem glabrous to puberulent |
| V. beckwithii |
| 6' Lower 3 petals cream, bases with deep yellow area; stem glabrous |
| V. hallii |
| 3' Leaf generally ± entire to deeply lobed (seldom dissected) |
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| 7. Petals white to blue or purple, without yellow |
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| 8. Stem branched; leaves basal and cauline |
| V. adunca |
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| 9. Petals white, dark-veined or not |
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| 10. Leaf blade elliptic to ovate, longer than wide nw Klamath Ranges, 100500 m |
| V. primulifolia subsp. occidentalis |
| 10' Leaf blade ovate to reniform, generally as wide as or wider than long |
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| 11. Rhizome < 5 mm diam; spur white; leaf blade thin, not leathery, (sub)entire; native; mtns |
| V. macloskeyi |
| 11' Rhizome 520 mm diam; spur violet; leaf blade thick, leathery, ± toothed; alien; San Francisco Bay Area, South Coast |
| 2 V. odorata |
| 9' Petals blue (sometimes very pale) to purple |
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| 12. Leaf glabrous; rhizome thin; North Coast |
| V. palustris |
| 12' Leaf ± glabrous or finely hairy; rhizome thick; Klamath Ranges, San Francisco Bay Area, South Coast, San Bernardino Mountains, Warner Mountains, East of Sierra Nevada |
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| 13. Plant stoloned; leaf finely hairy; alien; San Francisco Bay Area, South Coast |
| 2 V. odorata |
| 13' Plant not stoloned; leaf ± glabrous; native; Klamath Ranges, San Bernardino Mountains, Warner Mountains, East of Sierra Nevada |
| V. sororia subsp. affinis |
| 7' Petals yellow to ± orange, or white with yellow base and spur |
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| 14. Petals white inside, with generally yellow base and spur, lower 3 veined purple-red |
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| 15. Leaf blade base generally tapered; basal blade midvein 1040 mm; plant glabrous |
| V. cuneata |
| 15' Leaf blade base generally truncate to deeply cordate; basal blade midvein 1060 mm; plant finely hairy |
| V. ocellata |
| 14' Petals yellow to ± orange inside, generally veined dark brown to purple |
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| 16. Stems few, erect, unbranched below; basal leaves 04; cauline leaves and peduncles restricted to upper stem |
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| 17. Upper 2 petals yellow outside; cauline leaf ovate-cordate to widely reniform; moist places |
| V. glabella |
| 17' Upper 2 petals purple to brown-purple outside; cauline leaf diamond-shaped to reniform, entire to dissected; dry places |
| V. lobata |
| 18. Cauline leaf diamond-shaped to generally deltate, entire to toothed |
| subsp. integrifolia |
| 18' Cauline leaf ± ovate to generally reniform, palmately lobed or dissected, segments 312, generally entire |
| subsp. lobata |
| 16' Stems 0many, prostrate to erect, branched below; basal leaves 06; cauline leaves and peduncles on lower and upper stem |
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| 19. Plant stoloned; leaf evergreen, leathery, generally purple-spotted on 1 or both sides coastal forests |
| V. sempervirens |
| 19' Plant not stoloned; leaf not evergreen, not leathery, not purple-spotted |
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| 20. Basal leaves 0; cleistogamous flowers 0; petals orange-yellow fruit glabrous |
| V. pedunculata |
| 20' Basal leaves 16; cleistogamous flowers present; petals yellow to lemon-yellow |
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| 21. Basal blade 1.56 × longer than wide, 1580 mm, linear to obovate; cauline blade 210 × longer than wide |
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| 22. Plant white-tomentose n&c High Sierra Nevada |
| V. tomentosa |
| 22' Plant glabrous to densely hairy (not white-tomentose) |
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| 23. Leaf generally entire |
| V. bakeri |
| 23' Leaf toothed, jagged, or wavy (seldom entire) |
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| 24. Cauline leaf blade 325 mm wide, linear to ± ovate; peduncle 2090 mm |
| V. pinetorum |
| 25. Plant canescent, 410 cm; leaves 310 mm wide, basal 4095 mm, cauline 3080 mm s High Sierra Nevada |
| subsp. grisea |
| 25' Plant glabrous to hairy, 622 cm; leaves 425 mm wide, basal 50200 mm, cauline 30150 mm |
| subsp. pinetorum |
| 24' Cauline leaf blade 1445 mm wide, elliptic to ± ovate; peduncle 40180 mm |
| V. praemorsa |
| 26. Cauline leaf blade much longer than wide, generally irregularly toothed or wavy, base generally tapered |
| subsp. linguifolia |
| 26' Cauline leaf blade slightly longer than wide, generally regularly toothed, base ± truncate to subcordate |
| subsp. praemorsa |
| 21' Basal blade generally 11.5 × longer than wide, 1050 mm, ovate to round; cauline blade generally < 2.5 × longer than wide |
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| 27. Leaf canescent above; plant generally 613 cm; peduncle 30100 mm; uncommon East of Sierra Nevada, Mojave Desert |
| V. aurea |
| 27' Leaf glabrous to hairy (not canescent) above; plant 135 cm; peduncle 15170 mm; widespread |
| V. purpurea |
| 28. Plant 112 cm; stem generally buried, little branched or elongated by late summer; lower petal (including spur) generally < 11 mm |
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| 29. Cauline leaf generally entire; plant 112 cm |
| subsp. integrifolia |
| 29' Cauline leaf generally crenate to deeply toothed; plant 411 cm |
| subsp. venosa |
| 28' Plant 435 cm; stem generally not buried, clearly branched and elongated above by late summer; lower petal (including spur) generally > 11 mm |
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| 30. Cauline leaf deeply toothed |
| subsp. mohavensis |
| 30' Cauline leaf entire, jagged, shallowly toothed, or lobed |
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| 31. Leaf generally green tinged purple, generally glabrous above; lower petal (including spur) generally < 13 mm; peduncle generally < 13 cm; 5002500 m, generally montane forest |
| subsp. purpurea |
| 31' Leaf generally gray-green (± without purple), puberulent; lower petal (including spur) generally 13+ mm, or peduncle > 13 cm, or both; 4001800 m, generally foothill communities |
| subsp. quercetorum
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