- Family: aster (Asteraceae)
- Habitat: wet meadows, moist woods and thickets
- Height: 3-6 feet
- Flower size: flowerheads 1-1/2 to 2-1/2 inches across
- Flower color: pink to magenta
- Flowering time: July to September
- Origin: native
On swamp thistle, the involucre (the vase-shaped structure beneath the flowers) has cobwebby white hairs, and it is often slightly sticky.