The Collaborative International Dictionary of English v.0.48:

Anatropal \A*nat"ro*pal\, Anatropous \A*nat"ro*pous\, a. [Gr. ?
   up + ? to turn.] (Bot.)
   Having the ovule inverted at an early period in its
   development, so that the chalaza is as the apparent apex; --
   opposed to orthotropous. --Gray.
   [1913 Webster]

WordNet (r) 3.0 (2006):

anatropous
    adj 1: (of a plant ovule) completely inverted; turned back 180
           degrees on its stalk [syn: anatropous, inverted]
           [ant: amphitropous]