Sagittaria lancifolia

Lore & Background

Sagittaria lancifolia is conspicuous for its large, lance-shaped leaves that grow up from underground rhizomes and its showy, white three-petaled flowers at the end of long, thick stalks. Each flower has three green sepals, three white or pink-tinged petals, at least six stamens, and pistils which may be in separate flowers. The plant grows in fresh or brackish water and is commonly found in ditches, marshes, swamps, and along the shores of lakes and streams.

The species reproduces both asexually through spreading rhizomes and sexually through production of copious achenes—dry fruits each carrying a single seed. Achenes are dispersed by animal vectors and through hydrochory (dispersal by wind, water, or gravity). They germinate only under light, with or without available fluid, but germination period is shorter when submersed in water. Temperature is a factor, with 100% germination occurring at 20 °C (68 °F), and germination is reduced in anaerobic conditions. Growth is also dependent on temperature.

Field studies in Louisiana marshlands examined the plant's sensitivity to in-situ burning of applied crude oil. Although application and burning of South Louisiana Crude oil had short-term negative effects on growth rate, plant recovery over time was just as rapid as in plots that were oiled but not burned. This suggests that allowing a polluted marsh to degrade and recover without burning is a viable option, while burning is viable when rapid recovery is needed on sensitive lands.

Reader's Guide

Sagittaria lancifolia holds significance as a native plant of the southeastern United States, Mexico, Central America, the West Indies, and northern South America, and has become naturalized on the Island of Java in Indonesia. Its common name 'duck potato' refers to the large potato-like corms that form underground, which are a notable food source. The plant's reproductive strategies—asexual via rhizomes and sexual via achenes dispersed by animals and water—allow it to colonize fresh and brackish water habitats such as ditches, marshes, swamps, and shorelines. Its germination requirements (light, temperature-dependent, and shorter when submersed) and sensitivity to anaerobic conditions inform its ecological niche. Field studies in Louisiana marshes demonstrate its resilience to crude oil pollution: while burning oiled plants initially reduces growth, recovery matches that of unburned oiled plants over time, offering management options for polluted wetlands. The plant's large lance-shaped leaves and white three-petaled flowers make it visually distinctive in aquatic settings.

Did You Know?

• The common name 'duck potato' comes from the large potato-like corms that form underground.
• Achenes germinate only under light, and germination is 100% at 20 °C (68 °F).
• Field studies in Louisiana marshes showed that oiled and burned plants recovered as rapidly as oiled but unburned plants over time.