| Asclepias californica | California Milkweed, Greene's milkweed | Apocynaceae | | 2 | 1 |
| Asclepias currasavica | Blood Flower | Apocynaceae | Asclepias aurantiaca Salisb. Asclepias bicolor Moench Asclepias cubensis Wender. Asclepias margaritacea Hoffmanns. ex Schult. Asclepias nivea curassavica (L.) Kuntze. Asclepias curassavica (correct name) | 0 | 1 |
| Asclepias fascicularis | Mexican milkweed | Apocynaceae | A. fasciculata Hemsl. A. macrophylla Nutt. A. mexicana non Cav. | 1 | 0 |
| Asclepias hallii | Purple Silkweed, Hall's milkweed | Apocynaceae | | 3 | 1 |