Stelis concinna 
Stelis convallaria 
Stelis eublepharis 
Stelis restrepioides 
Stelis sclerophylla 
Stelis superbiens 
Stenoptera peruviana 
Sternbergia clusiana 
Sternbergia colchiciflora 
Stinking Iris 
Striking Masdevallia 
Striped coralroot 
Sugar orchid 
Summer Snowflake 
Sun orchid 
Swamp Lily 
Swamp sun orchid 
Sword-leaf Oberonia 
Sword-Shaped Leaf Elleanthus 
Sydney Rock Orchid 
Syrian Iris 
Tachira Lepanthes 
Taeniophyllum hirtum 
Tall leek orchid