Chufa

Cyperus esculentus is a species of plant in the sedge family widespread across much of the world. It is found in most of the Eastern Hemisphere, including Southern Europe, Africa and Madagascar, as well as the Middle East and the Indian subcontinent. C. esculentus is cultivated for its edible tubers, called earth almonds or tiger nuts (due to the stripes on their tubers and their hard shell), as a snack food and for the preparation of horchata de chufa, a sweet, milk-like beverage. Cyperus esculentus can be found wild, as a weed, or as a crop. It is an invasive species outside its native range, and is readily transported accidentally to become invasive. In many countries, C. esculentus is considered a weed. It is often found in wet soils such as rice paddies and peanut farms as well as well-irrigated lawns and golf courses during warm weather.

Source: Wikipedia