It is native to the Americas, where it is most common in Chile and Argentina and can be found in northern South America and sections of the southwestern and southeastern United States.

Phalaris angusta is an annual grass reaching as much as 2.5 meters tall.

The inflorescence is a narrow cylindrical spike of rough-haired, pointed spikelets.

Calves that eat the grass develop neurological signs such as tremors and convulsions and gross examination of their brain tissue reveals large blue-green lesions.

[2] Some cattle and sheep die suddenly after grazing in pastures of the grass, while some linger with signs of neurological compromise.