Vexilary aestivation

Vexillar Vex"il*lar, Vexillary Vex"il*la*ry, [Cf. F. vexillaire, L. vexillarius a standard bearer.] [1913 Webster] 1. Of or pertaining to an ensign or standard. [1913 Webster]

2. (Bot.) Of or pertaining to the vexillum, or upper petal of papilionaceous flowers. [1913 Webster]

{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. [1913 Webster]