Poa mannii is a rare species of grass known by the common names Mann's bluegrass and Olokele Gulch bluegrass. It is endemic to Hawaii, where it is limited to the island of Kauai. It is threatened by the loss and modification of its habitat. It is a federally listed endangered species of the United States. Besides feral goats, the plant and its habitat are threatened by introduced species of plants, fire, hurricanes, and landslides.