Digitaria is a genus of plants in the grass family native to tropical and warm temperate regions but can occur in tropical, subtropical, and cooler temperate regions as well. Common names include crabgrass, finger-grass, and fonio. They are slender monocotyledonous annual and perennial lawn, pasture, and forage plants; some are often considered lawn pests. Digitus is the Latin word for "finger", and they are distinguished by the long, finger-like inflorescences they produce.

Fonio, also sometimes called findi or acha, is the term for two cultivated grasses in the genus Digitaria that are important crops in parts of West Africa. The nutritious food with a favorable taste is a vital food source in many rural areas, especially in the mountains of Fouta Djalon, Guinea but it is also cultivated in Mali, Burkina Faso, Ivory Coast, Nigeria, and Senegal. The global fonio market was estimated at 721,400 tonnes in 2020. Guinea annually produces the most fonio in the world, accounting for over 75% of the world's production in 2019. The name fonio is from Wolof foño. In West Africa, the species black fonio (Digitaria iburua) and white fonio (Digitaria exilis) are cultivated, whereby the latter is the economically more important crop.