| | 1. Annual or biennial, taproot generally slender |
| |
| | 2. Calyx tube clearly 16–30-veined |
| |
| | 3. Styles 5; corolla blade clearly 2-lobed; fruit valves 10; flower pistillate |
| 3 S. latifolia subsp. alba |
| | 3' Styles generally 3; corolla blade entire to notched; fruit valves 3; flower bisexual |
| |
| | 4. Calyx 18–26 mm; petal appendages 2–5 mm |
| S. conoidea |
| | 4' Calyx 8–12 mm; petal appendages 0 |
| S. multinervia |
| | 2' Calyx tube clearly 10-veined |
| |
| | 5. Pedicel and calyx glabrous; upper leaves linear to oblanceolate; most upper internodes sticky |
| S. antirrhina |
| | 5' Pedicel and calyx hairy; upper leaves lanceolate to narrowly oblong; internodes not sticky |
| |
| | 6. Pedicels 0–5 mm; flowers generally 1 per node; inflorescence ± 1-sided |
| |
| | 7. Calyx densely short-hairy, not glandular; petal blade 5–12 mm, lobed ± 1/2 length; style exserted; inflorescence bracts thin, ± translucent |
| S. dichotoma |
| | 7' Calyx glandular-hairy especially on veins; petal blade 2–5 mm, entire to notched; style included; inflorescence bracts thick, opaque |
| S. gallica |
| | 6' Some pedicels > 5 mm; some nodes with 2–3 flowers; inflorescence not 1-sided |
| |
| | 8. Styles 5; fruit not developing; calyx tube veins not clearly net-like, lobes generally 3–6 mm, acute to acuminate; flowers staminate |
| 3 S. latifolia subsp. alba |
| | 8' Styles generally 3; fruit developing, valves 3; calyx tube veins net-like above middle, lobes 6–13 mm, generally long-tapered; flowers bisexual |
| S. noctiflora |
| | 1' Perennial, from short rhizome or simple to branched, woody caudex |
| |
| | 9. Corolla bright red; stems ± weak, prostrate to decumbent |
| |
| | 10. Cauline leaves widely lanceolate to ovate; fruit ovoid |
| S. californica |
| | 10' Cauline leaves linear to narrowly lanceolate; fruit ± oblong to ovoid |
| S. laciniata subsp. major |
| | 9' Corolla white, reddish, purple, or yellowish white to green; stems stiff, decumbent to generally erect |
| |
| | 11. Calyx clearly ± inflated (papery in S. vulgaris) |
| |
| | 12. Calyx 12–20 mm, short-hairy, 10- or 20-veined, lobes 3–6 mm; fruit ovoid |
| 3 S. latifolia subsp. alba |
| | 12' Calyx 7–10 mm, generally glabrous, faintly 10–15-veined, lobes 1–3 mm; fruit subspheric |
| S. vulgaris |
| | 11' Calyx not clearly inflated or papery in fruit |
| |
| | 13. Petal claw tapered to blade; appendages 0 |
| |
| | 14. Calyx lobes 4–5 mm, slightly < tube; petal 4-lobed, claw ± fusiform, short-woolly below middle; s High Sierra Nevada |
| S. aperta |
| | 14' Calyx lobes 1–2 mm, << tube; petals entire to slightly notched, claw gradually tapered to blade, glabrous to sparsely short-hairy below middle; s High Cascade Range, n High Sierra Nevada |
| S. invisa |
| | 13' Petal claw and blade junction generally abrupt, often narrowed; appendages 2–6, 0.5–4 mm |
| |
| | 15. Petal blade generally 4–8-lobed |
| |
| | 16. Calyx 15–40 mm; corolla 20–30 mm |
| |
| | 17. Petals pink to rose-red, blades 14–20 mm; s High Cascade Range |
| S. occidentalis subsp. longistipitata |
| | 17' Petals yellowish white, blades 7–10 mm; Transverse Ranges, Peninsular Ranges |
| S. parishii |
| | 16' Calyx 5–20(25) mm; corolla generally < 20 mm (< 30 mm in S. occidentalis subsp. occidentalis) |
| |
| | 18. Calyx tube generally < or = 10 mm |
| |
| | 19. Calyx tube cylindric, length > width; stamens and styles clearly exserted; petal claw short-woolly |
| S. lemmonii |
| | 19' Calyx tube bell-shaped, length ± = width; stamens and styles = corolla or slightly exserted; petal claw glabrous or ciliate at base |
| |
| | 20. Petals 5–10 mm, blade 4-lobed; fruit stalk glabrous; flowers generally ascending to erect; calyx lobes generally < 2 mm |
| 2 S. menziesii |
| | 20' Petals 12–20 mm, blade 4–6(8)-lobed; fruit stalk puberulent; flowers nodding to ± spreading; calyx lobes 2–5 mm |
| S. campanulata |
| | 21. Leaves 2–10 mm wide, linear to lanceolate |
| subsp. campanulata |
| | 21' Leaves 10–30 mm wide, lanceolate to ± round |
| subsp. glandulosa |
| | 18' Calyx tube generally > 10 mm |
| |
| | 22. Upper cauline leaves generally overlapping or exceeding pedicels; calyx canescent to soft-white-hairy; petal blade ± = claw length, lobes > 10 mm |
| S. hookeri |
| | 22' Flowers located well above cauline leaves; calyx short-glandular-hairy; petal blade 1/3–1/2 × claw length, lobes < 8 mm |
| |
| | 23. Calyx ± elliptic; caudex much-branched; stems < 30 cm; basal leaves ± fleshy, densely tufted |
| 2 S. grayi |
| | 23' Calyx cylindric; caudex 1 or few-branched; stems generally > 30 cm; basal leaves generally thin, not fleshy, not tufted |
| |
| | 24. Fruit stalk 4–7 mm; petal blade 7–17 mm; calyx > 15 mm |
| S. occidentalis subsp. occidentalis |
| | 24' Fruit stalk 2–5 mm; petal blade 3–7 mm; calyx generally < 15(18) mm |
| |
| | 25. Petal appendages 2, deeply cut or fringed; petal claw and stamen filament ciliate at base |
| S. bernardina |
| | 25' Petal appendages 4–6, entire; petal claw and stamen filament glabrous |
| S. oregana |
| | 15' Petal blade 2-lobed, sometimes short-toothed near base |
| |
| | 26. Basal and lower cauline leaves densely tufted, fleshy, linear to narrowly oblanceolate, generally < 40 mm, < 5 mm wide; flowering stems generally < 30 cm |
| |
| | 27. Seeds 2–3 mm; calyx 8–10 mm; petal blades 3–5 mm; basal leaves 1–5 mm wide |
| 2 S. grayi |
| | 27' Seeds 1–2 mm; calyx 9–15 mm; petal blades 2.5–3.5 mm; basal leaves 1.5–3.5 mm wide |
| |
| | 28. Walls between calyx hair cells clear; seed surface honeycombed throughout; petal lobes generally entire; High Sierra Nevada, East of Sierra Nevada |
| S. sargentii |
| | 28' Walls between calyx hair cells purple; seed surface honeycombed, margins papillate; petal lobes short-toothed near base; High Cascade Range (Mount Shasta, Lassen Peak) |
| S. suksdorfii |
| | 26' Basal leaves not densely tufted, not fleshy, generally lanceolate to oblanceolate, some > 30 mm, > 5 mm wide; some flowering stems > 30 cm |
| |
| | 29. Petals < 10 mm, calyx 5–7 mm; petal appendages < 0.5 mm |
| 2 S. menziesii |
| | 29' Petals > 10 mm, calyx 7–20 mm; petal appendages > 1 mm |
| |
| | 30. Flowers nodding; stamens and style much exserted |
| S. bridgesii |
| | 30' Flowers spreading to generally erect; stamens and style included to = corolla |
| |
| | 31. Pedicel and calyx puberulent, not glandular |
| |
| | 32. Calyx base truncate to rounded in fruit; basal leaves and lower internodes glabrous to sparsely puberulent |
| S. douglasii |
| | 32' Calyx base narrowed in fruit; basal leaves and lower internodes moderately to densely puberulent, sometimes ± finely scabrous |
| S. verecunda |
| | 33. Stem scabrous; petal claws ciliate throughout; leaves ± thick, stiff |
| subsp. andersonii |
| | 33' Stem short-soft-hairy or puberulent; petal claws ciliate at base; leaves ± thin, flexible |
| |
| | 34. Pedicel and calyx puberulent; lower leaves 5–9 cm; mtns > 500 m |
| subsp. platyota |
| | 34' Pedicel and calyx ± short-soft-hairy; lower leaves 3–6 cm; coastal < 400 m |
| subsp. verecunda |
| | 31' Pedicel and calyx glandular-hairy |
| |
| | 35. Most basal leaves > 10 mm wide, oblanceolate, lanceolate, or elliptic |
| |
| | 36. Cauline leaves << basal leaves; cauline leaf pairs < 3; fruit stalk 1–2 mm, glabrous or sparsely puberulent; calyx lobe veins wider than tube veins; > 1200 m |
| S. nuda |
| | 36' Cauline leaves gradually reduced upward; cauline leaf pairs > 4; fruit stalk 3–6 mm, puberulent to woolly; calyx lobe and tube vein width ± equal, ± puberulent; < 300 m |
| S. scouleri subsp. grandis |
| | 35' Basal and lower cauline leaves 0 or withered (if present, most < 10 mm wide, linear to narrowly oblanceolate) |
| |
| | 37. Middle cauline leaves 5–10 mm wide; calyx lobe margins membranous |
| S. marmorensis |
| | 37' Middle cauline leaves < 6 mm wide; calyx lobe margin generally translucent |
| S. verecunda (see 33 for subspp.)
|