Northern Prairie Wildlife Research Center
Northeast Wetland Flora
Field Office Guide to Plant Species
Pontederia cordata L.
- Family: Pickerel Weed (Pontederiaceae)
- Flowering: June-November
- Field Marks: This species is recognized by its leaves with a heart-shaped base and the
spike-like panicle of showy purple flowers.
- Habitat: Shores, often in shallow standing water, and in fresh water tidal areas.
- Habit: Perennial herb from thick, widely creeping rhizomes.
- Stems: Upright, smooth, stout, with 1 leaf and a terminal spike-like panicle.
- Leaves: Basal as well as one on the stem, ovate to narrowly lanceolate, rounded or pointed at the tip, heart-shaped at the base, smooth, without teeth but sometimes wavy-edged, up to 8 inches long; leaf stalks rather stout, smooth, up to 3 1/2 inches long.
- Flowers: Many crowded into a terminal, spike-like panicle up to 8 inches long, the panicle subtended by a leafless sheath; flowers 2-lipped, white-hairy, at least when young.
- Sepals and Petals: 6, united below to form a tube 1/4-1/3 inch long, the lobes 1/4-1/2 inch long, forming 3 lips, the upper 3 lobes ovate, purple, with 2 yellow spots, the lower 3 lobes narrow and spreading, purple.
- Stamens: 6, attached to the sepals and petals but at different levels.
- Pistils: Ovary superior, smooth.
- Fruits: Ellipsoid, with 6 toothed ridges at the top, up to 1/2 inch long, enclosed by the base of the sepals and petals, 1-seeded; seeds 1/6-1/4 inch long.
- Notes: There is considerable variation in leaf shape, from broadly ovate to narrowly lanceolate. Some recent authors define these variations as varieties. Pontederia cordata var. cordata has strongly heart-shaped leaves, while P. cordata var. lanceolata has more lanceolate leaves.
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