Fern stitch (canvaswork)
Make a diagonal stitch across two intersections of the canvas from top left to bottom right. Take the needle under one thread of the canvas to the left and back to the surface.
Make the second diagonal stitch across two intersections of the canvas, ending three canvas threads across from the start of the first stitch.
Take the needle across back of the stitch and out one thread underneath the first stitch. Repeat the two diagonal stitches, each one a canvas thread beneath the last.
The next vertical row is started from the top again and worked down, meeting the previous row at the edge.
The stitch can vary in length and angle. By making the diagonal stitch across three threads and down one, for example, the angle of the stitch can be made considerably shallower.
Alternate rows could be worked top to bottom then bottom to top for a different final appearance.
Structure of stitch
Identifying Fern stitch (canvaswork)
Fern stitch is an overlapping band stitch that is always worked in the same direction.
Various Authors, The Royal School of Needlework Book of Embroidery (2018) , p.107
Mary Thomas, Mary Thomas’s Dictionary of Embroidery Stitches (1934) , p.96