When we take our final vows, part of the ceremony is receiving and wearing a crown of thorns. A real one. We use pyracantha (otherwise called, very appropriately, firethorn) to fashion the crown. Since our veils are white, symbolizing the Eucharist, the Mother Prioress tries not to draw any blood either through the thorns or when pinning the crown to the veil at the ceremony.
But it is a crown of thorns rather than flowers for a reason. It reminds us that we must be like our Spouse, the Crucified and should expect to suffer as he did. On the day of vows and jubilees the crown is worn throughout the day. On silver and golden jubilees of vows the crowns are worn again with the appropriate additions of silver and gold decorations.
Finally, when her earthly journey is completed, another crown is placed on the sisters as they lie in the coffin. But this time it is a crown of joyful victory…a crown of flowers symbolizing that the battle and race is over and the wedding feast has begun.