Vexillar /(?)/

Vex·il·lar

Vexillar
  1. Of or pertaining to an ensign or standard.
  2. Of or pertaining to the vexillum, or upper petal of papilionaceous flowers. (Bot.)

Phrases & Compounds
Vexilary aestivation
a mode of aestivation in which one large upper petal folds over, and covers, the other smaller petals, as in most papilionaceous plants.