| Scientific Name | Notes | Rarity Ranks | Common Name |
|---|---|---|---|
| Lessingia hololeuca | (historical-1940) | CNPS-EB: *A1x State CNPS: 3 | woolly-headed lessingia |
| Micropus amphibolus | (historical - 1955) | CNPS-EB: *A1x State CNPS: 3.2 | Mount Diablo cottonseed, Mt. Diablo cottonweed |
| Myosurus minimus subsp. apus | CNPS-EB: *A1? State CNPS: 3.1 | little mousetail | |
| Polygonum marinense | CNPS-EB: *A1x State CNPS: 3.1 | Marin knotweed |