Scutellaria galericulata
Skullcap
Scutellaria minor
Lesser Skullcap
Senecio cambrensis
Welsh Groundsel
Senecio inaequidens
Narrow-leaved Ragwort
Senecio vulgaris
Groundsel
Sequoia sempervirens
Coastal Redwood
Serratula tinctoria
Saw-wort
Sherardia arvensis
Field Madder
Sibthorpia europaea
Cornish Moneywort
Silene conica
Sand Catchfly
Silene dioica
Red Campion
Silene flos-cuculi
Ragged-Robin
Silene latifolia
White Campion
Silene noctiflora
Night-flowering Catchfly
Silene nutans
Nottingham Catchfly
Silene viscaria
Sticky Catchfly
Silene vulgaris
Bladder Campion
Sinapis alba
White Mustard
Sisymbrium officinale
Hedge Mustard
Smyrnium perfoliatum
Perfoliate Alexanders
Solanum chenopodioides
Tall Nightshade
Solanum dulcamara
Bittersweet
Solanum melongena
Eggplant
Soleirolia soleirolii
Mind-your-own-business