What is "chelone glabra"

Turtlehead \Tur"tle*head`\, n. (Bot.) An American perennial herb ( Chelone glabra) having white flowers shaped like the head of a turtle. Called also snakehead, shell flower, and balmony.

Chelone glabra (white turtlehead) is a plant. Its classification has in the past been controversial, but as a result of DNA sequence studies, it is now regarded as belonging to family Plantaginaceae (the plantain family).