| Scientific Name | Common Name(s) | Life History | Growth Form | |
|---|---|---|---|---|
|
Schinus molle | australian pepper , California pepper-tree, molle, pepper tree, Peruvian mastic-tree, Peruvian pepper-tree, pirul, Peruvian-mastictree, aguaribai (Spanish), pimientero falso (Spanish), rosépeppar (Swedish) | Perennial | tree |
|
Schinus polygama | Hardee peppertree, Chilean peppertree | Perennial | shrub |
|
Schinus terebinthifolia | Brazilian pepper tree, Christmas berry, Florida holly | Perennial | shrub |
|
Scilla siberica | Siberian Squill | Perennial | forb |
|
Scolymus hispanicus | goldenthistle, Spanish oysterplant, Spanish salsify | Biennial | forb |
|
Searsia lancea | African sumac, karee, willow rhus | Perennial | tree |
| Securigera varia | Purple crownvetch, trailing crownvetch | Perennial | forb | |
| Senecio angulatus | climbing groundsel, creeping groundsel, Cape ivy, canary creeer | Perennial | vine | |
|
Senecio angustifolius | Bitter Bush | Perennial | shrub |
| Senecio elegans | redpurple ragwort, purple ragwort, wild cineraria | Annual | forb | |
|
Senecio linearifolius | fireweed groundsel, linear-leaved Australian fireweed | Perennial | shrub |
| Senecio quadridentatus | cotton burnweed, cottonweed | Annual | forb | |
|
Senna artemisioides | Silver Senna | Perennial | shrub |
|
Senna didymobotrya | African senna, candelabra-tree, peanut-butter cassia | Perennial | shrub |
|
Senna multiglandulosa | glandular senna, buttercup bush | Perennial | shrub |
|
Solanum aviculare | New Zealand nightshade, kangaroo-apple, nightshade | Perennial | shrub |
|
Solanum carolinense | Carolina horsenettle , ball nightshade, ball-nettle, horse-nettle | Perennial | forb |
|
Sorbus alnifolia | Korean Mountain Ash | Perennial | tree |
| Sparaxis tricolor | Harlequin flower | Perennial | forb | |
| Spartium junceum | Spanish broom, Weaver's broom | Perennial | shrub | |
| Sphaeralcea munroana | orange globe mallow, Munro's globe mallow, white-stem globe mallow, desert mallow | Perennial | forb | |
|
Sphaerophysa salsula | Alkali swainsonpea, Austrian peaweed, red bladder-vetch | Perennial | forb |
|
Spiraea japonica | Japanese spirea, Japanese meadowsweet, maybush | Perennial | shrub |
| Spiraea japonica 'Gold Mound' | Gold Mound Spirea | Perennial | shrub | |
|
Sporobolus heterolepis | Prairie dropseed | Perennial | grass |