Sacred Column Cactus 
Saguaro cactus 
Salicornia virginica 
Salsola cyclophylla 
Salsola imbricata 
Salsola inermis 
Salsola oppositifolia 
Salsola schweinfurthii 
Salt Sandspurry 
Saltcedar 
Sand Catchfly 
Scented Sundew 
Schlumbergera orssichiana 
Schlumbergera russelliana 
Sea Campion 
Sea Grape 
Sea pink 
Sea Sandwort 
Sea-Purslane 
Seaberry Saltbush 
Senita cactus 
Serpentine springbeauty 
Shasta buckwheat 
Shield sundew