Northern Prairie Wildlife Research Center
Northeast Wetland Flora
Field Office Guide to Plant Species
Eupatoriadelphus purpureus (L.) R.M. King & H. Rob.
- Family: Composite (Compositae)
- Flowering: July-September
- Field Marks: This Joe-pye-weed has solid stems that are purple at least at the nodes and leaves in whorls of 2-5.
- Habitat: Rich woods, damp thickets.
- Habit: Perennial herb from thickened rootstocks.
- Stems: Upright, rather slender, branched or unbranched, solid, green, usually glaucous, dark purple at the nodes, usually smooth, up to 10 feet tall.
- Leaves: In whorls of 2-5, simple, lanceolate to ovate, pointed at the tip, tapering to the base, sharply toothed, smooth on the upper surface, smooth or short-hairy on the lower surface, up to 1 foot long, up to 6 inches wide, on short stalks.
- Flowers: 3-7 in heads with numerous heads in open, round-topped clusters up to 1 foot across; heads up to 1/2 inch high, pink or lilac, consisting only of disk flowers; bracts narrowly oblong.
- Sepals: 0.
- Petals: 5, united to form tubular disk flowers.
- Stamens: 5.
- Pistils: Ovary inferior, smooth.
- Fruits: Achenes ellipsoid, smooth, up to 1/4 inch long, subtended by white hairs.
- Notes: Gleason and Cronquist call this plant Eupatorium purpureum of the Asteraceae. The leaves have the odor of vanilla when crushed.
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