*snake's-head*

n. (Bot.) The Guinea-hen flower; -- so called in England because its spotted petals resemble the scales of a snake's head. Dr. Prior. [ 1913 Webster ]

Snake's-head iris (Bot.), an iridaceous plant (Hermodactylus tuberosus) of the Mediterranean region. The flowers slightly resemble a serpent's open mouth. [ 1913 Webster ]