| | 1. Leaves uniformly green, not mottled |
| |
| | 2. Perianth white with yellow base; stigma ± entire |
| |
| | 3. Perianth segments 10–20 mm, without sac-like folds at base |
| E. purpurascens |
| | 3' Perianth segments 18–35 mm, inner with small sac-like folds at base |
| |
| | 4. Perianth segments < 1/3 yellow; leaves 6–17 cm; flowers 1–3; Klamath Ranges, High Cascade Range |
| E. klamathense |
| | 4' Perianth segments 1/3–1/2 yellow; leaves 10–35 cm; flowers 1–8; s High Sierra Nevada |
| E. pusaterii |
| | 2' Perianth yellow; stigma entire or lobed |
| |
| | 5. Perianth segments 15–28 mm; style and filaments yellow; stigma entire or with lobes < 1 mm; flowers 1–10 |
| E. pluriflorum |
| | 5' Perianth segments 20–35 mm; style and filaments white; stigma entire or with slender, recurved, 2–4 mm lobes; flowers 1–5 |
| |
| | 6. Fresh perianth segments with narrow, pale zone at base; stigma lobes 2–4 mm; Klamath Ranges, North Coast Ranges |
| E. grandiflorum |
| | 6' Fresh perianth segments lacking pale zone at base; stigma entire or with lobes < 1 mm; c Sierra Nevada Foothills |
| E. tuolumnense |
| | 1' Leaves irregularly mottled with brown or white |
| |
| | 7. Filaments flat at base, generally > 1.5 mm wide; stigma lobes 4–6 mm |
| |
| | 8. Perianth segments pink with yellow base |
| E. revolutum |
| | 8' Perianth segments white with yellow base |
| E. oregonum |
| | 7' Filaments < 0.8 mm wide; stigma entire to lobed |
| |
| | 9. Perianth violet to pink with dark purple base |
| E. hendersonii |
| | 9' Perianth ± white with yellow base |
| |
| | 10. Style 4–10 mm; anthers yellow, white, or cream |
| |
| | 11. Anthers white to cream; style ± straight; bulblets 0 |
| E. citrinum |
| | 11' Anthers yellow; style ± bent; bulblets 0 or sessile |
| E. helenae |
| | 10' Style 10–15 mm; anthers white to cream |
| |
| | 12. Flower-stalk (when flowers > 1) branched well above leaves; bulblets 0 |
| E. californicum |
| | 12' Flower-stalk (when flowers > 1) branched near ground level; bulblets produced from long, slender rhizomes |
| E. multiscapoideum
|