Bitter herbs and romaine lettuce.

The Maror is placed in the center of the plate. One may use either peeled and grated raw horseradish or Romaine lettuce, or both.

The center of the plate represents the attribute of rachamim, mercy.

At first glance it would seem more appropriate to place the Maror on the left side, signifying the attribute of gevurot, severity, for Maror recalls the severity of our suffering in Egypt.

But, upon reflection, we realize that bitterness of spirit causes a manifestation of abundant mercy: the outpouring of an embittered soul, the intense bitterness one experiences when sensing how far removed one is from Divinity, arouses an abundance of mercy.

From this perspective, then, the Maror itself signifies mercy.