Puerto Rico Ghostplant 
Purple Allamanda 
Purple Gentian 
Purple rubber vine 
Redring milkweed 
Rhazya stricta 
Richardia brasiliensis 
Rosepink 
Rosy Milkweed Vine 
Rough bedstraw 
Round-leaved Gentian 
Rubia danaensis 
Rubia tenuifolia 
Rush Milkweed 
Samgamoli 
Sea Box 
Showy Milkweed 
Silkvine 
Singaporandia 
Skunkvine 
Slender Centaury 
Smaller fringed gentian 
Sore-mouth Bush 
Southern Cleavers