This print is characteristic of Morrison's practice as a painter: he makes outsized black and white linear images of plants, often copied from or inspired by earlier printed sources such as woodcut herbals. Here the layers of imagery - a knight on horseback seen through a screen of plants and lines - echo the layers of meaning and reference. There are direct references to the work of earlier printmakers - notably Durer in the horse and the body of the rider - and Rembrandt (the face of the rider is copied from a Rembrandt self-portrait). This layering explains the title: epithelium is the scientific name for the layering of meshes of cells in plants and bodies which form their outer structures.