Solidago
Solidaster
Sollya
Sonerila
Sophora
Sophrolaeliocattleya
Sorbaria
Sorbus
Sorghastrum
Sparaxis
Sparganium
Spartina
Spartium
Spathiphyllum
Spathodea
Sphaeralcea
Spigelia
Spiraea (spirea)
Solidaster
Sollya
Sonerila
Sophora
Sophrolaeliocattleya
Sorbaria
Sorbus
Sorghastrum
Sparaxis
Sparganium
Spartina
Spartium
Spathiphyllum
Spathodea
Sphaeralcea
Spigelia
Spiraea (spirea)
Sporobolus
Sprekelia
Stachys
Stachyurus
Stangeria
Stanhopea
Stapelia
Stapelianthus
Staphylea
Stauntonia
Stenanthium
Stenocactus
Stenocarpus
Stenocereus
Stenomesson
Stenotus
Stephanandra
Stephanocereus
Sprekelia
Stachys
Stachyurus
Stangeria
Stanhopea
Stapelia
Stapelianthus
Staphylea
Stauntonia
Stenanthium
Stenocactus
Stenocarpus
Stenocereus
Stenomesson
Stenotus
Stephanandra
Stephanocereus