Spergula arvensis
Corn Spurrey
Spergularia marina
Lesser Sea-spurrey
Spergularia media
Greater Sea-spurrey
Spergularia rubra
Sand Spurrey
Spergularia rupicola
Rock Sea-spurrey
Sphagneticola trilobata
Bay Biscayne Creeping-oxeye
Sphagnum denticulatum
Cow-horn Bog-moss
Spigelia anthelmia
West Indian Pinkroot
Spiraea canescens
Himalayan Spiraea
Spiraea x rosalba
Intermediate Bridewort
Spiranthes romanzoffiana
Irish Lady's-tresses
Spiranthes spiralis
Autumn Lady's-tresses
Spirodela polyrhiza
Greater Duckweed
Splachnum ampullaceum
Cruet Collar-moss
Stachys alpina
Limestone Woundwort
Stachys arvensis
Field Woundwort
Stachys byzantina
Lamb's-ear
Stachys germanica
Downy Woundwort
Stachys palustris
Marsh Woundwort
Stachys sylvatica
Hedge Woundwort
Stachytarpheta jamaicensis
Blue Porterweed
Stapelia variegata
Staphylea pinnata
Bladdernut
Stellaria alsine
Bog Stitchwort