| | 1. Perennial or subshrubs from woody caudex |
| |
| | 2. Perennial; root ± tuber-like; leaves deltate to ± cordate, 3–12 cm, nonglandular |
| B. grandiflora |
| | 2' Subshrubs; leaves linear to ovate, 1–3 cm, glandular |
| |
| | 3. Leaves 10–20 mm wide, ovate; fruit ± 7 mm |
| B. greenei |
| | 3' Leaves < 8 mm wide, linear to ± ovate; fruit 4–6 mm |
| B. oblongifolia var. linifolia |
| |
| | 4. Plant generally 10 dm or more |
| |
| |
| | 6. Heads 12–14 mm; phyllaries ± glabrous |
| B. californica |
| | 6' Heads 8–10 mm; phyllaries puberulent |
| B. desertorum |
| |
| | 7. Leaves linear; phyllaries 10–12 |
| B. longifolia |
| | 7' Leaves lanceolate to ovate; phyllaries ± 20 |
| |
| | 8. Leaves generally serrate |
| B. knappiana |
| B. multiflora |
| | 4' Plant generally 2–6 dm |
| |
| | 9. Phyllary tips spreading or recurved |
| |
| B. nevinii |
| |
| | 11. Stems glandular-hairy |
| B. microphylla |
| | 11' Stems tomentose-puberulent |
| B. watsonii |
| |
| | 12. Plants white-tomentose; heads ± 24 mm |
| B. incana |
| | 12' Plants green; heads generally 12–15 mm |
| |
| | 13. Outer phyllaries ovate |
| B. atractyloides |
| | 13' Outer phyllaries ± linear to widely lanceolate |
| |
| | 14. Leaves oblong to spoon-shaped, not leathery, entire; outer phyllaries linear-oblong, acute, ± 3 mm, puberulent to minutely tomentose |
| B. frutescens |
| | 14' Leaves ovate, leathery, generally sharply toothed; outer phyllaries widely lanceolate, long-tapered, ± 10 mm, generally minutely scabrous |
| B. arguta |
| | 15. Outer phyllaries ± entire |
| var. arguta |
| | 15' Outer phyllaries clearly dentate |
| var. odontolepis
|