Source : Webster's Revised Unabridged Dictionary (1913)

Orthotropal \Or*thot"ro*pal\, Orthotropous \Or*thot"ro*pous\, a.
   [Ortho- + Gr. ? to turn: cf. F. orthotrope.] (Bot.)
   Having the axis of an ovule or seed straight from the hilum
   and chalaza to the orifice or the micropyle; atropous.

   Note: This word has also been used (but improperly) to
         describe any embryo whose radicle points towards, or is
         next to, the hilum.

Source : WordNet®

orthotropous
     adj : (of a plant ovule) completely straight with the micropyle at
           the apex [ant: {campylotropous}]