I am stuck on 3 today - any help appreciated.
3d Term for a line of verse lacking a syllable in the last foot (10) - I have ?A?A?E???C
6d A tax levied on various goods brought into a town or city in some countries (6) - I have ?C?R?I
18a Part of the perianth of a flower with no differentiation between a petal or sepal (5) - I have ??P?L