| | 1. Ray flowers 0; outer pappus bristles very few — generally dry streambeds (sect. Ammodia) |
| H. oregona |
| | 2. Leaves on branches ± (sub)glabrous, ± densely glandular |
| |
| | 3. Leaves on branches generally > 13 mm, > 3 mm wide; outer phyllaries lanceolate-deltate; North Coast Ranges, Cascade Range, n&c South Coast Ranges |
| var. oregona |
| | 3' Leaves on branches generally < 13 mm, < 3 mm wide, ± scabrous; outer phyllaries ovate-deltate; s San Francisco Bay Area, South Coast Ranges |
| var. scaberrima |
| | 2' Leaves on branches ± densely hairy, sparsely glandular |
| |
| | 4. Stems generally branched below middle; leaves long-soft-hairy, appearing gray-green |
| var. compacta |
| | 4' Stems generally loosely branched above middle; leaves short-bristly, appearing green |
| var. rudis |
| | 1' Ray flowers present; outer pappus bristles generally many |
| |
| | 5. Annual to short-lived perennial herb; ray fruits ± glabrous; ray pappus 0 (sect. Heterotheca) |
| |
| | 6. Upper leaves not clasping; ± California Floristic Province, common, weedy |
| H. grandiflora |
| | 6' Upper leaves clasping; South Coast, Sonoran Desert, uncommon |
| H. psammophila |
| | 5' Perennial; ray fruits hairy; ray pappus present (sect. Phyllotheca) |
| |
| | 7. Corolla lobes ± sparsely hairy; leaf margins often wavy, hairs stiff or soft; Tehachapi Mountain Area, Central Western California, Southwestern California |
| H. sessiliflora |
| | 8. Upper leaf margins flat to weakly wavy, hairs ± 2 mm |
| |
| | 9. Lower stem sparsely woolly; upper leaves oblanceolate, little reduced, flat, strigose to long-woolly; North Coast, n Central Coast |
| subsp. bolanderi |
| | 9' Lower stem bristly; upper leaves elliptic to lanceolate, generally much reduced, sometimes wavy-margined, strigose and bristly; inland c&s California |
| subsp. echioides |
| | 8' Upper leaf margins distinctly wavy, hairs ± 1 mm |
| |
| | 10. Heads not subtended by leaf-like bracts; upper leaves whitish, stiff; Transverse Ranges and Peninsular Ranges > 200 m |
| subsp. fastigiata |
| | 10' Heads subtended by large leaf-like bracts; upper leaves green, not stiff; South Coast < 10 m |
| subsp. sessiliflora |
| | 7' Corolla lobes (sub)glabrous; leaf margins flat, hairs stiff; Cascade Range, Sierra Nevada, Modoc Plateau, sw Desert Mountains |
| H. villosa |
| | 11. Herbage ± densely strigose, generally glandless (except inflorescence) — Klamath Ranges, Cascade Range |
| var. villosa |
| | 11' Herbage ± sparsely hairy, ± glandular |
| |
| | 12. Mid-stem leaves (ob)lanceolate, ± sparsely strigose and glandular — Sierra Nevada, Modoc Plateau |
| var. hispida |
| | 12' Mid-stem leaves narrowly triangular-lanceolate, ± scabrous to bristly, ± densely glandular |
| |
| | 13. Stems 2–5 dm; mid-stem leaves ascending, flat; sw Desert Mountains |
| var. scabra |
| | 13' Stems 2–13 dm; mid-stem leaves very stiff, often reflexed, ± inrolled; s Sierra Nevada Foothills |
| var. shevockii
|