| 1. Inflorescence a peduncled pair of flowers |
| |
| 2. Corolla > 25 mm; climbing vine |
| L. japonica |
| 2' Corolla < 20 mm; erect shrub |
| |
| 3. Ovaries of flower pair fused or appearing so |
| |
| 4. Corolla yellowish, weakly 2-lipped; bracts generally 13, narrowly lanceolate; ovaries and berries tightly enclosed by fused inner bracts, appearing fully fused |
| L. cauriana |
| 4' Corolla dark red, strongly 2-lipped; bracts 0 or minute; ovaries and berries fused ± 2/3 |
| L. conjugialis |
| 3' Ovaries of flower pair obviously free |
| |
| 5. Bracts not leafy, not obscuring ovaries |
| L. tatarica |
| 5' Bracts leafy, forming a conspicuous involucre, ± enveloping ovaries |
| L. involucrata |
| 6. Plant generally < 9 dm; corolla yellow, tube ± wider upward; style and stigma well exserted; montane |
| var. involucrata |
| 6' Plant generally > 15 dm; corolla yellow, strongly tinged orange or red, tube cylindric; stigma rarely exserted; coastal |
| var. ledebourii |
| 1' Inflorescence a spike, generally ± interrupted twining or trailing shrubs |
| |
| 7. Ovary/hypanthium long, slender, generally sterile see note after generic description |
| |
| 7' Ovary/hypanthium short, round, fertile |
| |
| 8. Leaf 510 cm; corolla 1540 mm; inflorescence a dense, short spike; upper leaf pair fused around stem; Northwestern California, Cascade Range |
| |
| 9. Corolla orange, weakly 2-lipped; stamens and style little exserted |
| L. ciliosa |
| 9' Corolla ± yellowish white, strongly 2-lipped; stamens and style well exserted |
| L. etrusca |
| 8' Leaf 18 cm; corolla generally < 15 mm; inflorescence a ± long, interrupted spike; upper leaf pair fused around stem or not; widespread |
| |
| 10. Upper leaf pairs fused around stem; corolla hairy or not |
| |
| 11. Leaves generally with ± obvious stipules, at least toward inflorescence; corolla glandular-hairy |
| L. hispidula var. vacillans |
| 11' Leaves without stipules; corolla glabrous |
| L. interrupta |
| 10' Upper leaf pairs not fused around stem; corolla often hairy |
| L. subspicata |
| 12. Leaf < 2 × longer than wide; widespread (including Santa Barbara Co.) |
| var. denudata |
| 12' Leaf 34 × longer than wide; Western Transverse Ranges (Santa Barbara Co.) |
| var. subspicata
|