Northern Prairie Wildlife Research Center
Southern Wetland Flora
Field Office Guide to Plant Species
Rudbeckia maxima Nutt.
- Family: Aster (Asteraceae)
- Flowering: July-September
- Field Marks: This coneflower differs from all other coneflowers by its smooth and glaucous
leaves and stems and its dark cone up to nearly 3 inches long.
- Habitat: Edges of swamps, swales, marshes, moist open areas.
- Habit: Coarse perennial herb with short-branching, thick rootstocks.
- Stems: Upright, stout, branched or unbranched, smooth, glaucous, up to 9 feet tall.
- Leaves: Of 2 kinds: basal and lowest leaves on the stem ovate to ovate-elliptic to oblong to spatulate,
rounded at the tip, tapering to the base, up to 8 inches long, up to 4 inches wide, with or without a
few teeth, smooth, glaucous, with long leaf stalks; leaves on upper part of stem much smaller,
narrowed to a sessile or even clasping base.
- Flowers: Many flowers borne in a head, each head composed of 7-10 or more yellow ray flowers
surrounding a central columnar black or purple disk, the disk up to nearly 3 inches long; flowers of 2
kinds, the outer flat and ray-like, those in the disk tubular.
- Sepals: 0.
- Petals: Those of the ray flowers united to form a flat, yellow ray, 2- or 3-toothed at the tip, up to 2 1/2
inches long, turning downward; those of the disk flowers tubular with 5 lobes, purple or black, up to
1/5 inch long.
- Stamens: 5.
- Pistils: Ovary inferior.
- Fruits: Achenes up to 1/3 inch long, purplish gray, with a few teeth at the tip.
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