Snakemouth orchid 
Snow orchid 
Sobralia crocea 
Sobralia dichotoma 
Sobralia liliastrum 
Sobralia luerorum 
Sobralia pulcherrima 
Sobralia setigera 
South African Weed Orchid 
Southern Marsh Orchid 
Spathoglottis microchilina 
Spathoglottis pubescens 
Specklinea caulophryne 
Specklinia picta 
Sphinx Ladies Tresses 
Sphyrastelis ecuadorensis 
Splendid spider orchid 
Spotted Brassia 
spotted coralroot 
Spotted Sun Orchid 
Spring Ladies' Tresses 
Stanhopea jenischiana 
Stelis argentata 
Stelis concinna