| Salicaceae | Willow family |
| Santalaceae | Sandalwood family |
| Sapindaceae | Soapberry family |
| Sarraceniaceae | Pitcher-plant family |
| Saururaceae | Lizard's Tail family |
| Saxifragaceae | Saxifrage family |
| Scrophulariaceae | Figwort family |
| Selaginellaceae | Spike-moss family |
| Simaroubaceae | Quassia family |
| Smilacaceae | Greenbriar family |
| Solanaceae | Nightshade family |
| Staphyleaceae | Bladdernut family |