Scindapsus pictus
Satin Pothos
Scirpus sylvaticus
Wood Club-rush
Scleranthus annuus
Annual Knawel
Scleranthus perennis
Perennial Knawel
Scrophularia auriculata
Water Figwort
Scrophularia nodosa
Common Figwort
Scrophularia umbrosa
Green Figwort
Scutellaria galericulata
Skullcap
Scutellaria incarnata
Hoary Skullcap
Scutellaria minor
Lesser Skullcap
Sedum album
White Stonecrop
Sedum anglicum
English Stonecrop
Sedum sexangulare
Tasteless Stonecrop
Seemannia sylvatica
Bolivian Sunset
Selaginella martensii
Variegated Spikemoss
Selaginella willdenowii
Willdenow's Spikemoss
Senecio cambrensis
Welsh Groundsel
Senecio inaequidens
Narrow-leaved Ragwort
Senecio sarracenicus
Broad-leaved Ragwort
Senecio sylvaticus
Heath Groundsel
Senecio viscosus
Sticky Groundsel
Senecio vulgaris
Groundsel
Senna fistula
Golden Shower Tree
Sequoia sempervirens
Coastal Redwood
Sequoiadendron giganteum
Wellingtonia
Serratula tinctoria
Saw-wort
Setaria verticillata
Hooked Bristlegrass
Sibthorpia europaea
Cornish Moneywort
Sida acuta
Common Wireweed
Sida rhombifolia
Arrowleaf Sida
Silaum silaus
Pepper-saxifrage
Silene acaulis
Moss Campion
Silene armeria
Sweet-William 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
Simethis mattiazzii
Kerry Lily
Sinapis arvensis
Charlock
Sison amomum
Stone Parsley
Sisyrinchium bermudiana
Blue-eyed-grass
Smyrnium perfoliatum
Perfoliate Alexanders
Solandra grandiflora
Showy Chalicevine
Solanum aethiopicum
Ethiopian Eggplant
Solanum chenopodioides
Tall Nightshade
Solanum dulcamara
Bittersweet
Solanum torvum
Pendejera
Solidago canadensis
Canadian Goldenrod
Solidago gigantea
Early Goldenrod
Solidago virgaurea
Goldenrod
Sonchus arvensis
Perennial Sow-thistle
Sonchus asper
Prickly Sow-thistle
Sonchus oleraceus
Smooth Sow-thistle
Sonneratia caseolaris
Mangrove Apple
Sorbus aria
Common Whitebeam
Sorbus aucuparia
Rowan
Sorbus cambrensis
Welsh Whitebeam
Sorbus leyana
Ley's Whitebeam
Sorbus minima
Least Whitebeam
Sorbus porrigentiformis
Grey-leaved Whitebeam
Sorbus rupicola
Rock Whitebeam
Sorbus stenophylla
Llanthony Whitebeam
Sorbus torminalis
Wild Service-tree
Sorbus x motleyi
Sparganium angustifolium
Floating Bur-reed
Sparganium natans
Least Bur-reed
Spathiphyllum blandum
Pleasant Peace Lily