Placentation in which the ovules are borne on central axis and septa are absent is:

Placentation in which the ovules are borne on central axis and septa are absent is Free central and is found in Dianthus and Primrose.
In basal placentation, the placenta develops at the base of ovary and a single ovule is attached to it, as in sunflower, marigold.
When the placenta is axial and the ovules are attached to it in a multilocular ovary, the placentation is said to be axile, as in china rose, tomato and lemon.
In parietal placentation, the ovules develop on the inner wall of the ovary or on peripheral part. Ovary is one-chambered but it becomes two chambered due to the formation of the false septum, e.g., mustard and Argemone.