
If two or more Carpels are fused at their Margins such that a single Locule is created, the Placentae are generally located at the Sutures. This is called Parietal.
The area of the Placenta may be enlarged and may sometimes appear to divide the Locule into halves. This resembles Axile Placentation but it is still Parietal.

Model of A Syncarpous Gynoecium with Parietal Placentation.