Sequoiadendron giganteum
Wellingtonia
Serratula tinctoria
Saw-wort
Sherardia arvensis
Field Madder
Sibthorpia europaea
Cornish Moneywort
Sicyos edulis
Chayote
Sida rhombifolia
Arrowleaf Sida
Silaum silaus
Pepper-saxifrage
Silene dioica
Red Campion
Silene flos-cuculi
Ragged-Robin
Silene gallica
Small-flowered Catchfly
Silene noctiflora
Night-flowering Catchfly
Silene nutans
Nottingham Catchfly
Silene uniflora
Sea Campion
Silene viscaria
Sticky Catchfly
Silene vulgaris
Bladder Campion
Simethis mattiazzii
Kerry Lily
Sinapis arvensis
Charlock
Sisyrinchium bermudiana
Blue-eyed-grass
Smyrnium perfoliatum
Perfoliate Alexanders
Solandra grandiflora
Showy Chalicevine
Solanum dulcamara
Bittersweet
Solanum erianthum
Velvet Nightshade
Solanum nigrum
Black Nightshade
Solidago canadensis
Canadian Goldenrod