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
Setaria verticillata
Hooked Bristlegrass
Setaria viridis
Green Bristle-grass
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