1. 
[syn: shellflower, shell-flower, turtlehead, snakehead, snake-head, Chelone glabra]
The Collaborative International Dictionary of English v.0.48:
Turtlehead \Tur"tle*head`\ (t[^u]r"t'l-h[e^]d`), 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.
   [1913 Webster]
WordNet (r) 3.0 (2006):
Chelone glabra
    n 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
         [syn: shellflower, shell-flower, turtlehead,
         snakehead, snake-head, Chelone glabra]