This stitch is a newcomer composite stitch, which, although it fits well with the Irish embroidery technique, is not actually found on older traditional Mountmellick work.
It provides an attractive edging which works well on curved lines, and in spite of incorporating a number of stitches in each unit is relatively easy to learn and quick to do.
It can be used in all kinds of surface embroidery. It looks really nice in crewel work, with wool threads. It can be used to decorate crazy quilt seams. It can be used as a border stitch, and it can even be used for monogramming and the like. It even lends itself to being double sided or reversed, and looks good with extended tails.
Ref: Yvette Stanton 2016; Mountmellick embroidery; Vetty Creations P.33