In a syncarpous gynoecium, there can be one or more locules, and various possible types of placentation. This can be observed on cross- and lateral sections of the ovary.

A septum (= "wall") is an interior wall which separates the locules when two or more chambers occur. The presence of septa is characteristic of axile placentation.

The placentation is axile when there are septa which divide the ovary into two or more locules. The ovules are attached along the central axis, in the inner angle formed by the septa.

Parietal placentation: there is no septum, so that the ovary is unilocular. The ovules are borne on the inner surface of the ovary walls (or extensions of the walls).

Free-central placentation : the ovules are borne on a central column which is not connected to the walls of the ovary by septa, i.e. there is only one locule, and the column does NOT reach the top of the ovary (bottom and top figures on the right).

Placentation can be also deduced (generally more easily) from the observation of older ovaries, and fruits (while stamens have to be observed on fresh or even non-open flowers).But sometimes, septa tend to secondarily disappear in ovaries with axile placentation. Thus when a cross-section of an ovary or a fruit show only one locule, it is necessary to also observe a longitudinal section of the ovary to say whether the placentation is free-central (the column does not reach the top of the ovary) or axile (the column reaches the top of the ovary).