The Collaborative International Dictionary of English v.0.48:

Acotyledon \A*cot`y*le"don\ (#; 277), n. [Gr. 'a priv. + ?
   anything cup-shaped. See Cotyledon.] (Bot.)
   A plant which has no cotyledons, as the dodder and all
   flowerless plants.
   [1913 Webster]