1. Perennial of western North America having white flowers
   - white prairie aster

Type of: aster

• genus Stellaria
• genus Stenocarpus
• genus Stenochlaena
• genus Stenopelmatus
• genus Stenopterygius
• genus Stenotaphrum
• genus Stenotomus
• genus Stenotus
• genus Stentor
• genus Stephanomeria
• genus Stephanotis
• genus Stercorarius
• genus Sterculia
• genus Sterna
• genus Sternotherus
• genus Stevia
• genus Sticherus
• genus Stictomys
• genus Stictopelia
• genus Stizolobium
• genus Stizostedion
• genus Stokesia
• genus Storeria
• genus Strekelia
• genus Strelitzia