| | 1. Petals < or = sepals; styles ± 1 mm; fruit chamber 1, placentas parietal |
| |
| | 2. Plant prostrate to decumbent, from matted stolons, 3–25 cm; leaves 3–7 mm; flowers generally 1–7 (often 1) per flower-stem; common, generally montane |
| H. anagalloides |
| | 2' Plant erect, 20–60 cm; leaves 10–25 mm; flowers many in compound inflorescences; uncommon, east-central Sacramento Valley, adjacent n Sierra Nevada Foothills |
| H. mutilum |
| | 1' Petals >> sepals; styles 3–10 mm; fruit chambers 3, placentas axile |
| |
| | 3. Shrub, stem generally > 2 m; sepal ciliate; uncommon |
| H. canariense |
| | 3' Perennial, stem generally < 1 m; sepal margin glabrous; common |
| |
| | 4. Leaf linear to lanceolate, generally folded, tip acute; stems many, from woody caudex |
| H. concinnum |
| | 4' Leaf ± elliptic or oblong, flat, obtuse; stems few from taproot or rhizome |
| |
| | 5. Leaf elliptic; sterile axillary branches generally < 2 cm; fruit 3-lobed |
| H. formosum var. scouleri |
| | 5' Leaf narrowly oblong; sterile axillary branches generally 2–10 cm; fruit unlobed |
| H. perforatum
|