\Vex"il*lar\, Vexillary \Vex"il*la*ry\, [Cf. F.
vexillaire, L. vexillarius a standard bearer.]
1. Of or pertaining to an ensign or standard.
2. (Bot.) Of or pertaining to the vexillum, or upper petal of
   papilionaceous flowers.
{Vexilary [ae]stivation} (Bot.), a mode of [ae]stivation in
   which one large upper petal folds over, and covers, the
   other smaller petals, as in most papilionaceous plants.