Seaside Heliotrope          

Sedge          

Seep Monkeyflower      

Seepweed          

Sego Lily          

Selfheal          

Seneca Snakeroot          

Sensitive Fern          

Sensitive Plant          

Serviceberry          

Sessileleaf Bellwort          

Shadscale Saltbush      

Shagbark Hickory      

Shaggy Dwarf Morning-glory          

Shaggy Fleabane          

Shaggy Soldier          

Sheathed Pondweed          

Shining Willow      

Shinyleaf Spirea          

Shootingstar          

Shortawn Foxtail      

Shortbeak Arrowhead          

Shortbeak Sedge          

Shortbristle Needle And Thread          

Shorthair Goldenrod          

Shortray Fleabane          

Shortspike Watermilfoil          

Shortstalk Chickweed          

Shortstalk False Bindweed          

Showy Buttercup          

Showy Goldenrod          

Showy Locoweed      

Showy Milkweed      

Showy Ticktrefoil          

Shrubby Cinquefoil          

Shrubby Fivefingers          

Shy Wallflower          

Sibbaldiopsis          

Siberian Bugseed          

Siberian Elm      

Siberian Peashrub      

Siberian Yarrow          

Sicklepod          

Sidebells Wintergreen