Sagittaria latifolia Willd.

Duck Potato

© DETenaglia

Family - Alismataceae

Habit - Perennial forb. Rhizomes, corms, and stolons variously present.

Stems - Aerial stems absent.

Leaves - All basal, simple, entire, long-petiolate, 10-150 cm long. Petioles somewhat inflated and rounded or less commonly flattened. Blades of rare submerged leaves absent or linear. Blades of emergent leaves sagittate to hastate. Venation with several pairs of main veins arching from the base of the midrib and rejoining near the apex and the tips of the lobes (when present), these connected by finer, angled veins running parallel to one another.

	Leaf adaxial.
© SRTurner

	Leaf abaxial.
© SRTurner

	Pressed leaves. Leaves nearly always have basal lobes, but these can be quite variable in width.
© DETenaglia

Inflorescence - Racemes with whorled flowers, sometimes branched near the base, ascending or erect. Bracts at inflorescence nodes 0.4-1.3 cm long, free or fused at the base, boat-shaped, rounded to acute at the apex. Lower 1-5 whorls of flowers pistillate, with ascending, unthickened pedicels 10-60 mm long. Upper flower whorls staminate.

	Inflorescence. This view mostly shows staminate flowers. A few pistillate flowers are visible near the bottom.
© SRTurner

	Bracts. Relatively broad and short-tapered at the tips.
© SRTurner

Flowers - Mostly unisexual. Sepals ovate, persistent, reflexed in fruit. Stamens many, the filaments longer than the anthers, not swollen basally, glabrous. Pistils many, in a dense spiral cluster on the globose, expanded receptacle. Styles terminal or lateral.

	Staminate flower.
© SRTurner

	Pistillate flowers.
© SRTurner

	Sepals.
© DETenaglia

Fruits - Numerous achenes in a dense, headlike cluster on an expanded receptacle. Achenes flattened, obovate, 2.5-4.0 mm long, the beak 0.6-1.6 mm long, narrowly triangular, spreading at a right angle to the body of the fruit.

	Infructescence.
© SRTurner

	Achenes. The achene beak spreads at a right angle from the body of the achene, rather than in an ascending direction.
© SRTurner

Flowering - June - October.

Habitat - Pond margins, mud flats, ditches, sloughs, marshes, wet open areas.

Origin - Native to the U.S.

Lookalikes - Other members of the genus, especially S. brevirostra and S. calycina.

Other info. - This common denizen of mud flat areas occurs across most of Missouri, though it is less common toward the west and north of the Missouri River. It also occurs across the continental U.S., but is most common in the eastern 2/3 of the country.

Plants in the Sagittaria genus are recognized by their arrowhead-shaped leaves on long petioles arising from the base of the plant (though some members of the genus lack basal lobes on the leaves), and elongate inflorescences with whorled flowers. Differentiation of Sagittaria latifolia from its sibling S. brevirostra relies on fairly subtle characters. The inflorescence bracts in Sagittaria latifolia are relatively short and blunt (books often say "boat-shaped"), whereas bracts of S. brevirostra have long-tapered points. Also, the achenes of S. brevirostra have ascending beaks, rather than the right-angle spreading beaks shown in the photo above.

Duck potato is an edible species which has long been used as food by native peoples as well as wildlife. The corms can be eaten raw or roasted, fried, or boiled, and reportedly have a flavor similar to potatoes or chestnuts. They can also be dried and ground into flower. Buds and fruits are also edible. The plant has been used medicinally.

Photographs taken along the shores of the Current River, Shannon County, MO., 8-17-03 (DETenaglia); also near Treloar, Warren County, MO, 8-2-2011, Shaw Nature Reserve, Franklin County, MO, 08-11-2011, Onondaga Cave State Park, Crawford County, MO, 08-20-2014, and Marais Temps Clair Conservation Area, St. Charles County, MO, 08-14-2017 (SRTurner).