Oldenlandia corymbosa, commonly known as Flat-Top Mille Graines or Old World Diamond-flower, is an annual herb that is native to tropical and subtropical regions of Africa. It is typically found in wet grasslands, along roadsides, in wastelands, and in rice paddies, where it thrives in moist conditions. This plant usually grows to a height and width of 0.5-1 feet (0.15-0.3 meters), forming a low, spreading mat. The flowers of Oldenlandia corymbosa are small, white, and not particularly showy, blooming in the summer months. The plant’s inconspicuous nature often leads to it being overlooked, despite its resilience.

Oldenlandia corymbosa is valued for its ability to grow in challenging conditions, including waterlogged soils and areas with poor drainage. It is often used in cultivation for erosion control or as a ground cover in wet areas. While it is not commonly grown for ornamental purposes, its adaptability makes it a useful plant in restoration projects or for filling in difficult spots in the landscape. It prefers full sun to part shade and can tolerate a range of soil types, including loam and clay, but it requires high amounts of water to thrive. There are no popular garden cultivars of this species, and it is generally free from serious pests and diseases. However, its ability to self-seed prolifically can make it a concern in some regions outside its native range, so care should be taken to manage its spread.CC BY-SA 4.0