Smyrnium perfoliatum
Perfoliate Alexanders
Solandra grandiflora
Showy Chalicevine
Solanum dulcamara
Bittersweet
Solanum erianthum
Velvet Nightshade
Solanum nigrum
Black Nightshade
Solidago canadensis
Canadian Goldenrod
Solidago gigantea
Early Goldenrod
Solidago virgaurea
Goldenrod
Sonchus arvensis
Perennial Sow-thistle
Sorbus aucuparia
Rowan
Sorbus minima
Least Whitebeam
Sorbus torminalis
Wild Service-tree
Sparganium erectum
Branched Bur-reed
Sparganium natans
Least Bur-reed
Spergula arvensis
Corn Spurrey
Spergularia marina
Lesser Sea-spurrey
Spergularia media
Greater Sea-spurrey
Spergularia rubra
Sand Spurrey
Spergularia rupicola
Rock Sea-spurrey
Sphagneticola trilobata
Bay Biscayne Creeping-oxeye
Spiranthes romanzoffiana
Irish Lady's-tresses
Spiranthes spiralis
Autumn Lady's-tresses
Splachnum ampullaceum
Cruet Collar-moss
Stachys arvensis
Field Woundwort