| | 1. Annual (biennial); root slender, short |
| |
| | 2. Leaf blade ± compound — leaflets 3, pinnately lobed; petals > 8 mm |
| G. robertianum |
| | 2' Leaf blade deeply lobed to dissected; petals generally < 7 mm |
| |
| | 3. Sepals acute; sepals, petals generally < 4 mm |
| |
| | 4. Fruit body transversely wrinkled, glabrous |
| G. molle |
| | 4' Fruit body smooth, minutely strigose |
| G. pusillum |
| | 3' Sepals awned, awn 1–2 mm; sepals, petals generally > 4 mm |
| |
| | 5. Pedicel 10–30 mm, > flower; fruit beak 3–5 mm |
| G. bicknellii |
| | 5' Pedicel 2–10 mm, ± = flower; fruit beak 2–3 mm |
| |
| | 6. Pedicel hairs stiff, straight to curving downward; fruit hairs ascending, ± 1 mm |
| G. carolinianum |
| | 6' Pedicel hairs glandular, spreading; fruit hairs spreading, < 1 mm |
| G. dissectum |
| | 1' Perennial; underground caudex thick, scaly, ± carrot-like |
| |
| | 7. Sepals 3–5 mm, petals 4–8 mm; fruit beak < 1 mm |
| |
| | 8. Stem, petiole hairs ± spreading or curving downward, petals generally 6–8 mm |
| G. potentilloides |
| | 8' Stem, petiole hairs appressed, pointing downward; petals generally 4–6 mm |
| G. retrorsum |
| | 7' Sepals 6–14 mm, petals > 10 mm; fruit beak > 2 mm |
| |
| | 9. Leaf blade ± compound; sepal hairs coarse, purplish |
| G. anemonifolium |
| | 9' Leaf blade deeply lobed to dissected; sepal hairs soft, glandular or not, white |
| |
| | 10. Petal surface glabrous, base ciliate; style branches < 3 mm |
| G. oreganum |
| | 10' Petal surface soft-hairy in lower half; style branches > 3 mm |
| |
| | 11. Pedicel hairs tipped with red to purple glands |
| G. richardsonii |
| | 11' Pedicel hairs tipped with white to yellow glands |
| |
| | 12. Petal surface soft-hairy over lower 1/2; style branches 6–9 mm; Sierra Nevada, Southwestern California |
| G. californicum |
| | 12' Petal surface soft-hairy over lower 1/3–1/5; style branches 4–5 mm; Klamath Ranges, Modoc Plateau |
| G. viscosissimum
|