Snowball Cactus 
Snowball Old Man 
Sorrel 
Sour fig 
Spanish Aizoon 
Spergularia diandra 
Spiked cockscomb 
Spinach 
Spinacia turkestanica 
Spiny pincushion cactus 
Spotted lady's thumb 
Spring Sandwort 
St. Helena Hogweed 
Star chickweed 
Starry Campion 
Stenocereus queretaroensis 
Stenocerueus pruinosus 
Sticky Catchfly 
Sticky mouse-ear chickweed 
Strapwort 
Strawberry Hedgehog Cactus 
Suaeda palaestina 
Suaeda vermiculata 
Succulent Catchfly