UMass Extension Weed Herbarium
| Common Name | Scientific Name | Family Name | |
|---|---|---|---|
| salsify, yellow | Tragopogon dubius | Asteraceae (Compositae) - Aster or Sunflower Family | |
| sandbur, longspine | Cenchrus longispinus | Poaceae (Graminae) - Grass Family | |
| sandspurry, red | Spergularia rubra | Caryophyllaceae - Pink Family | |
| sandwort, thymeleaf | Arenaria serpyllifolia | Caryophyllaceae - Pink Family | |
| scouring rush | Equisetum hyemale | Equisetaceae - Horsetail Family | |
| selfheal | see - heal-all | ||
| shepherd's-purse | Capsella bursa-pastoris | Brassicaceae (Cruciferae) - Mustard Family | |
| showy tick-trefoil | see - tickclover, hoary | ||
| silvergrass, amur | Miscanthus sacchariflorus | Poaceae (Graminae) - Grass Family | |
| skunk cabbage, common | Symplocarpus foetidus | Araceae - Arum Family | |
| smartweed, hedge | Polygonum scandens | Polygonaceae - Smartweed or Buckwheat Family | |
| smartweed, lady's thumb | Polygonum persicaria | Polygonaceae - Smartweed or Buckwheat Family | |
| smartweed, Pennsylvania | Polygonum pensylvanicum | Polygonaceae - Smartweed or Buckwheat Family | |
| snakeroot, white | Eupatorium rugosum | Asteraceae (Compositae) - Aster or Sunflower Family | |
| snapdragon, wild | see - toadflax, old field | ||
| soapwort | see - bouncing bet | ||
| sorrel, field | see - sorrel, red | ||
| sorrel, red | Rumex acetosella | Polygonaceae - Smartweed or Buckwheat Family | |
| sorrel , sheep | see - sorrel, red | ||
| sourgrass | see - woodsorrel, creeping | ||
| sourgrass | see - woodsorrel, yellow | ||
| sourgrass | see - sorrel, red | ||
| sowthistle, annual | Sonchus oleraceus | Asteraceae (Compositae) - Aster or Sunflower Family | |
| sowthistle, common | see - sowthistle, annual | ||
| sowthistle, creeping | see - sowthistle, perennial | ||
| sowthistle, field | see - sowthistle, perennial | ||
| sowthistle, perennial | Sonchus arvensis | Asteraceae (Compositae) - Aster or Sunflower Family | |
| sowthistle, spiny | Sonchus asper | Asteraceae (Compositae) - Aster or Sunflower Family | |
| sowthistle, spiny-leaved | see - sowthistle, spiny | ||
| speargrass | see - bluegrass, annual | ||
| speedwell, common | Veronica officinalis | Scrophulariaceae - Figwort Family | |
| speedwell, corn | Veronica arvensis | Scrophulariaceae - Figwort Family | |
| speedwell, ivy leaf | Veronica hederifolia | Scrophulariaceae - Figwort Family | |
| speedwell, purslane | Veronica peregrina | Scrophulariaceae - Figwort Family | |
| speedwell, thymeleaf | Veronica serpyllifolia | Scrophulariaceae - Figwort Family | |
| spring beauty, narrowleaf | Claytonia virginica | Portulacaceae - Purslane Family | |
| spurge, cypress | Euphorbia cyparissias | Euphorbiaceae - Spurge Family | |
| spurge, Hungarian | see - spurge, leafy | ||
| spurge, leafy | Euphorbia esula | Euphorbiaceae - Spurge Family | |
| spurge, prostrate | see - spurge, spotted | ||
| spurge, spotted | Euphorbia maculata | Euphorbiaceae - Spurge Family | |
| St. Johnswort | Hypericum perforatum | Hyperiacaceae - St. Johnswort Family | |
| staghorn | see - sumac, staghorn | ||
| star-of-Bethlehem | Ornithogalum umbellatum | Liliaceae - Lily Family | |
| starweed | see - chickweed, common | ||
| sticklewort | see - agrimony | ||
| stickseed, Virginia | see - beggarslice | ||
| sticktight | see - beggarticks | ||
| stickwort | see - agrimony | ||
| stickywilly | see - bedstraw, catchweed |