Plantago princeps is a rare species of flowering plant in the plantain family known by the common name ale. It is endemic to Hawaii, where it is known from the islands of Hawaii, Kauai, Oahu, Molokai, and Maui. Like other Hawaiian Plantago, it is known as kuahiwi laukahi, or laukahi kuahiwi. It is a federally listed endangered species of the United States. This plant is threatened by feral ungulates such as pigs and goats, and introduced species of plants invading its habitat.