Synonyms for Snakehead (same or very similar meaning)
WordNet sense 1 (showy perennial of marshlands of eastern and central North America having waxy lanceolate leaves and flower with lower part creamy white and upper parts pale pink to deep purple):
shellflower, shell-flower, snake-head, turtlehead, Chelone glabraFrom the ODE community, based on WordNetadd/edit