Satyrium maculatum – synonym of Neotinea maculata
Satyrium viride – synonym of Coeloglossum viride
Scilla hispanica – synonym of Hyacinthoides hispanica
Scilla non-scripta – synonym of Hyacinthoides non-scripta
Senecio mikanioides – synonym of Delairea odorata
Serapias helleborine L. var. latifolia – synonym of Epipactis helleborine
Sparganium affine – synonym of Sparganium angustifolium
Sparganium diversifolium – synonym of Sparganium emersum
Sparganium minimum – synonym of Sparganium natans
Sparganium ramosum – synonym of Sparganium erectum
Sparganium simplex – synonym of Sparganium emersum
Spiranthes autumnalis – synonym of Spiranthes spiralis