Chamaecrista rotundifolia, round-leaf cassia, also known as pasto rastiero, roundleaf sensitive pea, and Wynn cassia, is a short-lived perennial or self-generating annual plant belonging to the Fabaceae family and Caesalpinioideaesubfamily. It originated in North America, Mesoamerica, the Caribbean, and Tropical South America but is grown in other parts of the world today. It grows in dry soils and areas of low rainfall, as well as in low-fertility and acidic soils with high levels of solubilized aluminum. It can also reduce erosion and runoff over time. These factors make it a potential asset to farmers in the African Subtropics and elsewhere where soil quality is a barrier to farming. It serves as a source of feed for livestock and acts as a green fertilizer, raising soil quality and nutrient content which can improve yields. These combined benefits make round-leaf cassia a potential solution to many problems faced by poor farmers and their communities.
Round-leaf cassia is a fast covering perennial forage legume. Its sub-woody, semi-erect stem is covered in small hairs and can grow up to 1 metre in height, with a shallow tap-root. Some identifiable physical traits are its small axillary yellow flowers (depending on the season) and the characteristic round bifoliolate leaves for which it is named. Round-leaf Cassia grows mainly in the summer, but remains active during the spring and autumn months and has two flowering seasons, one in spring and another in summer. It is self-fertilizing and produces a good amount of seed on its own through natural reseeding