hemigamous

from The Collaborative International Dictionary of English v.0.48

Hemigamous \He*mig"a*mous\, a. [Hemi- + Gr. ? marriage.] (Bot.)
   Having one of the two florets in the same spikelet neuter,
   and the other unisexual, whether male or female; -- said of
   grasses.
   [1913 Webster]