Northern Prairie Wildlife Research Center
Northeast Wetland Flora
Field Office Guide to Plant Species
Eupatoriadelphus maculatus (L.) R.M. King & H. Rob.
- Family: Composite (Compositae)
- Flowering: July-September
- Field Marks: This Joe-pye-weed, with its whorls of 4-5 leaves, differs from other Joe-pye-weeds by its flat-topped inflorescence and its 8-22 flowers in each head.
- Habitat: Meadows, damp-soils.
- Habit: Perennial herb with fibrous roots.
- Stems: Upright, usually unbranched, not hollow, short-hairy at least near the inflorescence, purple-speckled, up to 4 feet tall.
- Leaves: In whorls of 4-5, simple, lanceolate to lance-ovate, long-pointed at the tip, tapering to the base, sharply toothed, smooth or slightly rough on the upper surface, short-hairy or smooth or rough on the lower surface, up to 6 inches long, up to 4 inches wide, sessile or with short stalks.
- Flowers: 8-22 in a head, with several heads in a flat-topped inflorescence, the heads cylindric, up to 1/2 inch high, purple, consisting only of disk flowers surrounded by oblong, round-tipped bracts.
- Sepals: 0.
- Petals: 5, united to form purple disk flowers.
- Stamens: 5.
- Pistils: Ovary inferior.
- Fruits: Achenes ellipsoid, up to 1/6 inch long, glandular.
- Notes: Gleason and Cronquist call this plant Eupatorium maculatum in the Asteraceae.
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