Field Marks: Purple flowers with usually 6 free
petals, a 4-angled stem, and leaves alternate, opposite, or even
whorled distinguish this species from all others.
Habitat: Margins of streams, wet meadows, ponds and
ditches, wet prairies, marshes, damp areas in rocky glades.
Habit: Herbaceous perennials from tufted roots.
Stems: 1-several, erect, stiffly branching, smooth,
4-angled, up to 3 1/2 feet tall.
Leaves: Upper usually alternate, lower usually
opposite or even whorled, simple, linear to broadly lanceolate,
pointed at the tip, more or less rounded at the base, the largest
up to 2 inches long, without teeth, smooth.
Flowers: Solitary in the axils of the upper leaves,
purple, with very short stalks.
Sepals: Usually 6, green, united below to form a tube
as long as or longer than the petals.
Petals: Usually 6, purple, free from each other, up
to 1/4 inch long.
Stamens: Usually 6, sometimes protruding above the
petals, sometimes not.
Pistils: Ovary superior.
Fruits: Capsules somewhat longer than broad, with
numerous minute seeds.