| | 1. Fruit evidently notched at base and tip (wings narrower there); leaflets or segments generally large (subg. Euryptera) |
| |
| | 2. Leaflets coarsely dentate or some 3-lobed (but not pinnately so) |
| |
| | 3. Leaf 1–2-ternate; fruit wings thickened, >> body in width; s California |
| L. lucidum |
| | 3' Leaf ternate-pinnate or 1–2-pinnate; fruit wings thin, = to slightly > body in width; n California |
| |
| | 4. Plant tall, 1.2–8 dm; fruit widely elliptic to round; Klamath Ranges |
| L. howellii |
| | 4' Plant low, 1.2–5 dm; fruit widely oblong; North Coast Ranges |
| L. repostum |
| | 2' Leaflets pinnately lobed and generally also toothed or irregularly cut |
| |
| | 5. Leaf blade > petiole; fruit 15–18 mm — s Channel Islands |
| L. insulare |
| | 5' Leaf blade < to ± = petiole; fruit 6–14 mm |
| |
| | 6. Leaflet spines weak; fruit wings = to > body in width; Central Coast, South Coast Ranges |
| L. parvifolium |
| | 6' Leaflet spines strong; fruit wings < body in width; High Sierra Nevada, East of Sierra Nevada |
| |
| | 7. Mature rays 25–50 mm; fertile pedicels 5–10 mm |
| L. rigidum |
| | 7' Mature rays 1–11 mm; fertile pedicels 0.1–1 mm |
| L. shevockii |
| | 1' Fruit not evidently notched at base and tip (wings not narrower there); leaflets or segments small to large |
| |
| | 8. Plant from a definite, spheric or elongate or irregularly thickened but generally not very deep-seated tuber (if uncertain, try 8' as well) |
| |
| | 9. Plant puberulent or hairy |
| |
| | 10. Bractlets not scarious, ± fused, reflexing |
| 3 L. macrocarpum |
| | 10' Bractlets ± scarious, free or fused, not reflexing |
| 5 L. nevadense |
| | 9' Plant glabrous or slightly roughened but not otherwise hairy |
| |
| | 11. Plant short-stemmed, from an elongate, often regularly narrowed tuber; rays suberect; fruit linear-oblong |
| 3 L. bicolor var. leptocarpum |
| | 11' Plant truly stless, from a ± spheric to ovoid tuber; rays ± spreading; fruit oblong to ovate |
| |
| | 12. Pedicel 5–16 mm; bractlet ± = flower; tuber < 4 cm wide |
| L. canbyi |
| | 12' Pedicel 0–2.5 mm; bractlet 0 or < flower; tuber < 2 cm wide |
| |
| | 13. Corolla white; petiole 3.5–10 cm; rays generally 15–35 mm |
| L. piperi |
| | 13' Corolla yellow; petiole 2–3 cm; rays 1–12 mm |
| L. stebbinsii |
| | 8' Plant from a generally elongated taproot that rarely ends in a deep-seated tuber |
| |
| | 14. Leaf dissected or compound, segments or leaflets generally few, generally large, generally wide |
| |
| | 15. Peduncle at top conspicuously swollen, inflated |
| L. nudicaule |
| | 15' Peduncle at top not swollen, not inflated, although rays sometimes webbed at base into prominent disk |
| |
| | 16. Stem 0 or very short, with 0–very few leaves; leaf 1–3-pinnate |
| |
| | 17. Stem base not fibrous; calyx 0 |
| L. martindalei |
| | 17' Stem base fibrous; calyx prominent (subg. Cynomarathrum) |
| L. parryi |
| | 16' Stem prominent, clearly with leaves; leaf 1–2-ternate-pinnate |
| |
| | 18. Herbage glaucous; leaflets wedge-shaped to obovate, 10–50 mm wide |
| L. californicum |
| | 18' Herbage green or grayish, not conspicuously glaucous; leaflets linear to ovate-lanceolate, 0.5–10 mm wide |
| L. triternatum |
| | 19. Ovary and often fruit densely puberulent |
| var. macrocarpum |
| | 19' Ovary and fruit glabrous |
| var. triternatum |
| | 14' Leaf dissected, segments generally many, small, sometimes long but then very narrow (see also L. parryi, which may key here) |
| |
| | 20. Ovary definitely puberulent or roughened or hairy, fruit hairy to rarely becoming glabrous |
| |
| | 21. Plants generally with a definite stem, stem leaves 1 or more |
| |
| | 22. Petals conspicuously tomentose |
| L. dasycarpum |
| | 23. Leaf segments linear; pedicels generally > fruit |
| subsp. dasycarpum |
| | 23' Leaf segments thread-like; pedicels generally < fruit |
| subsp. tomentosum |
| | 22' Petals ± glabrous, not tomentose |
| |
| | 24. Involucel 1-sided, reflexing, not scarious |
| 3 L. macrocarpum |
| | 24' Involucel not 1-sided, not reflexing, generally ± scarious |
| |
| | 25. Corolla white; cauline leaf sheaths inconspicuous |
| 5 L. nevadense |
| | 25' Corolla yellow; cauline leaf sheaths conspicuously swollen |
| |
| | 26. Herbage densely puberulent to glabrous, ovaries puberulent; bractlets generally obovate or oblanceolate, often overlapping |
| 2 L. utriculatum |
| | 26' Herbage, ovaries generally roughened; bractlets generally lanceolate to oblanceolate, not overlapping |
| 2 L. vaginatum |
| | 21' Plants truly stless, stem leaves 0 |
| |
| | 27. Corolla white, sometimes purple-tinged, anthers often purple |
| |
| | 28. Bractlets puberulent to hairy; leaf segments linear to lanceolate |
| L. ravenii |
| | 28' Bractlets generally glabrous; leaf segments linear to oblong |
| 5 L. nevadense |
| | 29. Ovary and often fruit densely finely hairy |
| var. nevadense |
| | 29' Ovary and fruit ± roughened |
| var. parishii |
| | 27' Corolla yellow or purple, anthers generally yellow |
| |
| | 30. Petiole > leaf blade; corolla generally purple, rarely yellow; fruit wings = to > body in width |
| L. mohavense |
| | 30' Petiole < leaf blade; corolla yellow, rarely purplish; fruit wings generally 1/2 body in width |
| L. foeniculaceum |
| | 31. Petals minutely ciliate; rays 2–14, 0.5–6 cm |
| subsp. fimbriatum |
| | 31' Petals, including margins, glabrous; rays generally 1, < 5 cm |
| subsp. inyoense |
| | 20' Ovary and fruit glabrous, sometimes roughened |
| |
| | 32. Plant definitely stemmed, stem leaves generally 2 or more |
| |
| | 33. Stem base with 1 or more scarious bladeless sheaths; fruit pumpkin-seed-like, wings thick, << body in width (subg. Leptotaenia) |
| L. dissectum |
| | 34. Fruit subsessile, fertile pedicels generally 1–3 mm, < sterile |
| var. dissectum |
| | 34' Fruit distinctly pedicelled, fertile pedicels generally 5–15 mm, > sterile |
| var. multifidum |
| | 33' Stem base without conspicuous bladeless sheaths; fruit wings thin, < to > body in width |
| |
| | 35. Corolla white, cream-colored or purplish |
| |
| | 36. Plant glabrous or slightly roughened; bractlets 0–few, inconspicuous |
| L. martindalei |
| | 36' Plant densely puberulent to tomentose; bractlets generally conspicuous, sometimes fused into a sheath |
| |
| | 37. Involucel 1-sided, reflexing, not scarious |
| 3 L. macrocarpum |
| | 37' Involucel generally radial, spreading, scarious |
| 5 L. nevadense |
| | 35' Corolla yellow, sometimes fading or drying white |
| |
| | 38. Leaves generally not crowded at stem base; fruit wings = or > body in width |
| |
| | 39. Herbage puberulent to glabrous, ovaries often puberulent — fruit generally glabrous |
| 2 L. utriculatum |
| | 39' Herbage, often ovaries minutely scabrous |
| 2 L. vaginatum |
| | 38' Leaves crowded at stem base; fruit wings < body in width |
| |
| | 40. Fruit linear-oblong; leaf segments linear, long, not crowded |
| 3 L. bicolor var. leptocarpum |
| | 40' Fruit oblong to ovate; leaf segments linear to oblong, very short, crowded |
| |
| | 41. Leaf green, shiny, sheath conspicuous; bractlets free, inconspicuous; Klamath Ranges |
| L. hallii |
| | 41' Leaf grayish, dull, sheath ± inconspicuous; bractlets fused at base into a conspicuous 1-sided scarious cup; High Cascade Range, n High Sierra Nevada, Great Basin Floristic Province |
| L. plummerae |
| | 32' Plant stless or nearly so, cauline leaves 0 or sometimes 1 or more at base of very short stem |
| |
| | 42. Fruit linear to narrowly oblong |
| |
| | 43. Stem base not fibrous; bractlets several, linear |
| 3 L. bicolor var. leptocarpum |
| | 43' Stem base fibrous; bractlets 0 |
| L. torreyi |
| | 42' Fruit oblong to nearly round |
| |
| | 44. Leaf segments thread-like or linear, long, not crowded; herbage green, often shiny |
| |
| | 45. Bractlets generally > 5, lanceolate to obovate, ± scarious, sometimes 0; pedicels stout — generally < fruit |
| L. caruifolium |
| | 46. Bractlets wide; fruit wings ± thin, wide |
| var. caruifolium |
| | 46' Bractlets narrow, sometimes 0; fruit wings very thick, narrow |
| var. denticulatum |
| | 45' Bractlets 0–5, thread-like to linear-lanceolate, not conspicuously scarious; pedicels slender |
| L. marginatum |
| | 47. Corolla yellow; interior foothills |
| var. marginatum |
| | 47' Corolla reddish purple; coast ranges |
| var. purpureum |
| | 44' Leaf segments lanceolate or oblong to ovate, rarely linear or thread-like, short, often crowded; herbage generally glaucous or grayish |
| |
| | 48. Herbage definitely puberulent to tomentose |
| |
| | 49. Leaf 2–3-pinnately dissected or compound; petiole sheathing in lower half; corolla white; Great Basin Floristic Province |
| 5 L. nevadense |
| | 49' Leaf ternate-pinnately dissected; petiole wholly sheathing; corolla yellow or purple; coast ranges |
| L. ciliolatum |
| | 50. Corolla generally yellow; fruit ribs thick; bractlets scarious-margined |
| var. ciliolatum |
| | 50' Corolla purple; fruit ribs thin; bractlets scarious ± throughout |
| var. hooveri |
| | 48' Herbage glabrous or minutely roughened to sparsely puberulent |
| |
| | 51. Pedicels slender, often > fruit; bractlets 0 |
| |
| | 52. Stem base fibrous; corolla pale yellow |
| L. congdonii |
| | 52' Stem base not fibrous; corolla purplish |
| L. engelmannii |
| | 51' Pedicels definitely < fruit; bractlets present |
| |
| | 53. Leaves obovate, basal sheaths straw-colored; in volcanic soils |
| L. peckianum |
| | 53' Leaves oblong to ovate, basal sheaths purplish; on serpentine |
| L. tracyi
|