The word “Katniss” is a common name for the edible, starchy tuber produced by the aquatic plant Sagittaria latifolia, also known as the broadleaf arrowhead or wapato. Derived from the Algonquin word for the plant, Katniss specifically designates the potato-like storage organ found at the end of the root system. This perennial herb, a member of the family Alismataceae, has a long history as a food source, particularly for indigenous populations across North America.
Botanical Structure of the Arrowhead Plant
The above-ground structure of Sagittaria latifolia is easily identifiable in wetland environments. The plant’s most striking characteristic is its leaves, which give it the common name arrowhead and the genus name Sagittaria (Latin for arrow). These leaves emerge above the water line and are characteristically sagittate, shaped like an arrowhead with two backward-pointing basal lobes. The leaves can be quite large, ranging from 6 to 30 centimeters in length, and stand on long, rigid stalks.
Rising above the leaves is a flowering stem, or raceme, which can reach heights of up to 90 centimeters. The inflorescence is composed of small, showy white flowers arranged in whorls of three, typically blooming from July through September. Each flower features three broad, white petals and three small, pale green sepals. The flowers are monoecious, meaning they are either male or female. Male flowers are generally positioned on the upper part of the stalk and possess 25 to 50 bright yellow stamens, while female flowers are below and identifiable by a sphere of green carpels.
The Edible Tuber
The starchy storage organ, which develops underground or underwater, is the primary focus of the plant. These organs, technically tubers or turions, are produced at the ends of slender runners, or rhizomes, extending from the main plant. The tubers are typically egg-shaped, measuring 0.5 to 5 centimeters in diameter, and are best harvested in the late summer or autumn as the leaves die back. Historically, the tubers were an important staple food for various Indigenous groups across North America, who often referred to them by names such as wapato or duck-potato.
The firm, starchy texture of the cooked tuber is often compared to that of a potato, and its flavor is similar to sweet chestnuts. Although the tubers can be eaten raw, they are generally cooked for 15 to 20 minutes to remove a mild bitterness, especially near the skin. Traditional preparation methods included boiling, roasting, or grinding them into a flour for use in gruels or bread. Harvesting often involved loosening the tubers from the muddy bottom, allowing the buoyant roots to float to the water’s surface for collection.
Aquatic Habitat and Geographical Range
Sagittaria latifolia is an obligate wetland plant, requiring consistently wet or submerged conditions to thrive. It is commonly found in shallow, slow-moving or stagnant freshwater habitats, such as river banks, sloughs, lakes, ponds, and emergent marshes. This perennial herb has strong roots that allow it to survive wide variations in water level. The plant favors full sun exposure and can grow in water depths up to about 60 centimeters.
The geographical distribution of the broadleaf arrowhead is extensive, covering a large portion of the Americas. It is native across southern Canada and most of the contiguous United States, with its range extending south into Mexico, Central America, and parts of northern South America, including Colombia and Venezuela. Its reliance on specific aquatic conditions dictates its presence in these regions, forming dense colonies in the wetlands where it is a prominent emergent species. The plant has also become naturalized in other regions globally, including parts of Europe and Hawaii.