Southern Wetland Flora
Field Office Guide to Plant Species
Sagittaria platyphylla (Englem.) J.G. Smith
- Family: Water Plantain (Alismataceae)
- Flowering: June
- Field Marks: This is one of the species of arrow-heads that lacks the pointed basal lobes of the leaves. The stalks of the fruiting heads are recurved. All the leaves that stand above the water are lanceolate to elliptic to ovate.
- Habitat: Swamps, wet ditches, ponds, marshes, shores, sloughs, often in standing water.
- Habit: Perennial herb with slender rhizomes.
- Stems: Upright, branched, smooth, up to 5 feet tall, bearing only flowers.
- Leaves: Of 2 types: those above water upright, lanceolate to elliptic to ovate, usually pointed at the tip, rounded or tapering to the base, up to 8 inches long, up to 3 1/2 inches wide, toothless and lobeless, smooth, with long stalks; those under water strap-shaped, up to 10 inches long, up to 3/4 inch wide, smooth, toothless and lobeless.
- Flowers: Male and female flowers borne separately but on the same plant near the tip of the leafless stems; flowers subtended by bracts up to 1/3 inch long.
- Sepals: 3, free from each other, up to 1/3 inch long, those of the female flowers turned downward and persistent in fruit.
- Petals: 3, white, free from each other, up to nearly 1 inch long, failing away long before the sepals.
- Stamens: Numerous.
- Pistils: Numerous, crowded on a receptacle; ovaries superior.
- Fruits: Achenes obovate, tapering to the base, about 1/10 inch long, winged, borne in a head; fruiting heads on recurved stalks.
- Notes: This species is sometimes considered to be a variety of Sagittaria graminea, but the fruiting heads of S. graminea are rarely recurved. This species is sometimes called Delta Duck Potato because of the tubers on the rhizomes. These tubers are a choice food for ducks.
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