Poa siphonoglossa is a rare species of grass known by the common names Kauai bluegrass and island 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. There are three species of Poa native to Hawaii, and all are endemic to Kauai. As of 1995, there were five populations of this species totalling about 50 individuals. The plant grows on moist, shady slopes.