Goeppertia allouia (syn. Calathea allouia), known as lerén or lairén in Spanish, and also known in English as Guinea arrowroot, and sweet corn root, and known in Trinidad and Tobago as topi tambu or topeetambo or topi-tamboo, is a plant in the arrowroot family, native to northern South America and the Caribbean, The name "allouia" is derived from the Carib name for the plant. Lerén is a minor food crop in the American tropics, but was one of the earliest plants domesticated by pre-historic Amerindians in South America.
Lerén is traditionally cultivated on a small scale. Its cultivation is declining as it has been replaced by other crops.
Lerén is usually cooked by boiling the tubers for 15 to 60 minutes, As food, lerén is often compared to water chestnut (Eleocharis dulcis) because lerén, like the water chestnut, retains its crispness despite being cooked. Boiled lerén has a taste similar to sweet corn, hence one of its common English names. The cooked tuber is covered with a thin, edible skin which is most easily peeled after cooking. Lerén is mostly eaten as an hors d'oeuvre or appetizer. Lerén tubers can be stored at room temperatures for up to three months, but do not tolerate refrigeration well.