- savine
- saw-wort
- scape
- scarlet sage
- scratch-bush
- savoy
- scale
- scammony
- scapelike
- schizocarp
- sclerenchyma
- scorpioid
- scutate
- scyphiferous
- scyphus
- sea fennel
- sea onion
- screw-pine
- scurvy-grass
- scutal
- sea kale
- sebestan
- seed-vessel
- secundine
- sedge
- seed-lobe
- seedage
- selaginella
- self-fertility
- self-fertilizing
- self-sown
- semination
- selenotropic
- self-fertilization
- self-impotent
- self-pollination
- self-sterility
- sepal
- septicidal
- septifragal
- sequoia
- sejugoust
- selenotropism
- self-sterile
- sell
- semi-double
- semidouble
- senega
- sengreen
- sensitive plant
- septenate
- seringa
- serotinous
- serpent-grass
- service
- service-tree
- setae
- setterwort
- sexifid
- shagbark
- shaggy
- shallot
- sessile
- seta
- setaceous
- sexual
- shaddock
- shade-grown
- shell-bark
- short-day
- short-stalked
- sigillate
- silicle
- silique
- shea
- sinistrorsal
- sinistrorse
- siliquose
- siliquous
- silver-berry
- sinuous
- sinus
- sisal
- smallage
- skull-cap
- snowdrop
- smash
- smilax
- smoke-plant
- snake-weed
- soap-berry
- solanceous
- sold
- soldanella
- sorb
- sorghum
- sorgo
- sori
- sorosis
- sorrel