Midwestern Arrowhead

Sagittaria brevirostra

midwestern_arrowhead_flowers.jpg

Photo of midwestern arrowhead male flowers and buds.
Flowers of Midwestern arrowhead arise in whorls of 2 or 3. As with our other six arrowhead species, the higher, male flowers are showy, with 3 white petals and many yellow stamens.
Edible
Other Common Name
Duck Potato; Wapato
Family

Alismataceae (arrowheads, water plantains)

Description

Midwestern arrowhead is an aquatic perennial herb growing on muddy banks. Flowers are erect, in mostly unbranched whorls of 3 (sometimes 2) on the flowering stalk. The flowers on the lowest 1–6 whorls are female, not showy, with many pistils that are densely packed into a single central receptacle; the female flowers will develop into green, rounded, burlike clusters of fruits, which turn brown in the fall. The flowers on the higher whorls of the stalks are male, showy, with 3 white petals and many yellow stamens. Blooms June–September. Leaves basal. Leaf blades arrowhead-shaped or halberd-shaped, on long petioles that are often inflated, angled, or ribbed.

Similar species: Seven species of arrowheads are recorded for Missouri. Midwestern arrowhead can be distinguished by its large leaf blades, and the bracts at the base of each whorl of flowers, which are ¾–2½ inches long, linear to lanceolate, with a narrowly acute tip. Also, the female flowers are on stalks ½–1½ inches long. Six other species are recorded for Missouri.

  • Kansas arrowhead or plains sagittaria (S. ambigua), uncommon in southwestern Missouri. It is one of the species whose leaves are lance-shaped or oval, but not arrow or halberd shaped.
  • Mississippi or hooded arrowhead (S. calcycina, syn. S. montevidensis ssp. calycina), scattered nearly statewide. Unlike our other arrowheads, the lower whorl of flowers are perfect, having stamens as well as the nubbin-like receptacle formed by a dense cluster of pistils.
  • Narrow-leaved, lance-leaved, grass-leaved, or grassy arrowhead (S. graminea), scattered statewide, mostly south of the Missouri River; true to its many names, its leaves are narrow and grasslike.
  • Duck potato, common arrowhead, wapato, or broadleaf arrowhead (S. latifolia), scattered statewide, more common south of the Missouri River. A species much used historically for its fairly large, edible corms. Leaf blades are arrow or halberd shaped. The achenes (seeds) have beaks that spread at a right angle to the body of the achene (not pointing upward). The nodes of the flower clusters have boat-shaped bracts to about ½ inch long, fairly rounded at the tip.
  • Delta arrowhead (S. platyphylla), uncommon in the Mississippi Lowlands of the Bootheel, plus one disconnected occurrence in Boone County. It is one of the species whose leaves are lance-shaped or oval, but not arrow or halberd shaped. In this species, as the lower, female flowers develop into globe-shaped clusters of fruits, their stalks thicken and bend downward.
  • Sessile-fruited arrowhead (S. rigida), scattered in Missouri, most commonly in the Ozarks, absent from the southeastern lowlands. The lower, female flowers, and the fruits that develop from them, are stalkless (sessile); the flower stalks abruptly bend at the lowest whorl of flowers. Leaf blades grasslike to oval, sometimes with a pair of small lobes at the base or arrow-shaped.
Size

Leaf length (including the stem): 4 to 60 inches.

midwestern_arrowhead_plants.jpg

Photo of midwestern arrowhead plants with pond surface in background.
Midwestern Arrowhead Plants
The leaves of many arrowhead species typically have arrowhead-shaped leaves.
Habitat and conservation

An emergent aquatic growing along muddy margins of ponds, ditches, sloughs, sluggish streams, and similar habitats. Sometimes flowers in dried mud.

image of Midwestern Arrowhead Duck Potato Wapato distribution map
Distribution in Missouri

Scattered nearly statewide.

Human connections

The starchy corms (potato-like “tubers”) of some arrowhead species have been baked, roasted, boiled, and even candied. Different species may produce corms of different sizes. Large-leaved species might develop larger corms than species with smaller leaves.

Native Americans valued the arrowhead species for food, drying the corms to eat in winter.

To harvest the corms, you can't just yank on the plant stalk; it tends to just break off. Historically, Native Americans waded into the water and used their feet to squish around in the muck with their toes, and release the corms, which float up to the surface. You could try using a rake. The corms are not positioned directly below where the plants are emerging from the water. They develop in a circle in the muck, at varying depths, around where the plants appear to be.

Most people report that uncooked duck potatoes, though edible, are not very tasty. Boiling or roasting them for about half an hour seems to be the trick. Remove the stalk, first, and then peel them after cooking.

The young stalks, tender, uncurling leaves, and tender flower stalks (before they bloom) may be cooked as greens.

The leaves of many arrowhead species typically have arrowhead-shaped leaves. The genus name, Sagittaria, refers to these sagittate leaves and shares its Latin linguistic root with the constellation Sagittarius, the archer.

Some Sagittaria species are commercially important as aquarium plants or aquatic ornamentals.

Ecosystem connections

Duck potatoes provide important food for wildlife. Ducks and geese feast on the seeds and/or the submerged corms.

Butterflies, bees, wasps, beetles, flies, and other insects cross-pollinate the flowers as they take nectar and pollen.

Other insects, such as some types of leaf beetles and weevils, aphids, grasshoppers, katydids, and certain larval caddisflies and moths, eat the leaves, stems, and/or rootstocks.

Some mammals, such as muskrat, also eat the plants.

Some aquatic turtles, including snapping turtle, painted turtles, river cooter, and red-eared sliders may eat parts of arrowhead plants.

Plants that grow rooted around the margins of ponds, lakes, ditches, and other sluggish bodies of water play an important role in filtering the water that passes through the soil from higher ground, removing and utilizing nutrients, including artificial fertilizers that might otherwise feed suspended algae that would turn the water green. They also stabilize banks and provide habitat for frogs and lots of other pond-dwelling animals.