Scutellaria minor
Lesser Skullcap
Sedum acre
Biting Stonecrop
Sedum anglicum
English Stonecrop
Senecio inaequidens
Narrow-leaved Ragwort
Senecio sarracenicus
Broad-leaved Ragwort
Senecio squalidus
Oxford Ragwort
Senecio sylvaticus
Heath Groundsel
Senecio viscosus
Sticky Groundsel
Senecio vulgaris
Groundsel
Serratula tinctoria
Saw-wort
Seseli libanotis
Moon Carrot
Sherardia arvensis
Field Madder
Sibthorpia europaea
Cornish Moneywort
Silaum silaus
Pepper-saxifrage
Silene conica
Sand Catchfly
Silene flos-cuculi
Ragged-Robin
Silene gallica
Small-flowered Catchfly
Silene noctiflora
Night-flowering Catchfly
Silene nutans
Nottingham Catchfly
Silene viscaria
Sticky Catchfly
Silene vulgaris
Bladder Campion
Sinapis alba
White Mustard
Sison amomum
Stone Parsley
Sisymbrium officinale
Hedge Mustard