ⓘ Aristida chaseae

                                     

ⓘ Aristida chaseae

Aristida chaseae is a rare species of grass known by the common name Chases threeawn. It is endemic to Puerto Rico, where it is known from two locations in the Cabo Rojo National Wildlife Refuge and the Sierra Bermeja. It is a federally listed endangered species of the United States. It cannot compete with introduced species of grasses, such as Brachiaria subquadripara, which are invading its habitat.

It is a perennial grass that produces a bundle of stems up to half a meter or slightly higher. Plants occurring in deep soils of Cabo Rojo tend to be more reliable than those growing in the poor soils of the Sierra Bermeja. Cabo Rojo plants are found in coastal grassland habitat, and those in the Sierra are growing on acidic clay soils with many rocky outcrops. The development of the Sierra Bermeja is a potential threat for grass and many other endemic plants.