The arches are cusped like the windows, but are stilted and segmental.
I agree that the cusped arch is not meant to imitate a leaf.
The cusped arch, too, was it actually not intended to imitate vegetation?
The tympana of the choir triforium arches are filled with plate tracery, quatrefoil and cusped.
It contains three pointed and cusped lancets on each side, and is without ...