Schismatoglottis calyptrata
Dukaruk
Schizostylis coccinea
Kaffir Lily
Schlumbergera bridgesii
Christmas cactus
Scilla autumnalis
Autumn Squill
Scilla bifolia
Alpine Squill
Scilla forbesii
Glory-of-the-snow
Scilla liliohyacinthus
Pyrenean Squill
Scilla luciliae
Boissier's Glory-of-the-snow
Scilla peruviana
Portuguese Squill
Scilla siberica
Siberian Squill
Scilla verna
Spring Squill
Scindapsus pictus
Satin Pothos
Scleranthus annuus
Annual Knawel
Scleranthus perennis
Perennial Knawel
Scorzoneroides autumnalis
Autumn Hawkbit
Scrophularia auriculata
Water Figwort
Scrophularia nodosa
Common Figwort
Scrophularia umbrosa
Green Figwort
Scutellaria galericulata
Skullcap
Scutellaria incarnata
Hoary Skullcap
Scutellaria minor
Lesser Skullcap
Scyphiphora hydrophylacea
Nilad
Sedum acre
Biting Stonecrop
Sedum album
White Stonecrop
Sedum anglicum
English Stonecrop
Sedum sexangulare
Tasteless Stonecrop
Seemannia sylvatica
Bolivian Sunset Gloxinia
Selenicereus undatus
Pitahaya
Sempervivum arachnoideum
Cobweb House-leek
Senecio cambrensis
Welsh Groundsel
Senecio inaequidens
Narrow-leaved Ragwort
Senecio sarracenicus
Broad-leaved Ragwort
Senecio squalidus
Oxford Ragwort
Senecio sylvaticus
Heath Groundsel
Senecio vernalis
Eastern Groundsel
Senecio viscosus
Sticky Groundsel
Senecio vulgaris
Groundsel
Senega paniculata
Root Beer Plant
Senna alata
Emperor's Candlesticks
Senna fistula
Golden Shower Tree
Senna obtusifolia
Sicklepod
Sequoia sempervirens
Coastal Redwood
Sequoiadendron giganteum
Wellingtonia
Serratula tinctoria
Saw-wort
Seseli libanotis
Moon Carrot
Sesuvium portulacastrum
Sea Purslane
Sherardia arvensis
Field Madder
Sibthorpia europaea
Cornish Moneywort
Sicyos edulis
Chayote
Sida acuta
Common Wireweed
Sida rhombifolia
Arrowleaf Sida
Silaum silaus
Pepper-saxifrage
Silene acaulis
Moss Campion
Silene armeria
Sweet-William Catchfly
Silene chalcedonica
Maltese-Cross
Silene conica
Sand Catchfly
Silene dioica
Red Campion
Silene flos-cuculi
Ragged-Robin
Silene gallica
Small-flowered Catchfly
Silene latifolia
White Campion
Silene noctiflora
Night-flowering Catchfly
Silene nutans
Nottingham Catchfly
Silene rupestris
Rock Campion
Silene uniflora
Sea Campion
Silene viscaria
Sticky Catchfly
Silene vulgaris
Bladder Campion
Silybum marianum
Milk Thistle
Simethis mattiazzii
Kerry Lily
Sinapis alba
White Mustard
Sinapis arvensis
Charlock