Although this edging is done in silver-gilt thread and not black silk thread, it is still evidence of button hole stitching on the edge of a blackwork embroidered coif and forehead cloth (circa 1600-1650, English) at the V&A Museum.
For more information on this coif and forehead cloth, as well as more pictures on this as well as other blackwork embroidered items, I definitely recommend visiting Angela Friedman's page here!
On her page, you'll find out where there was whip-stitching, the back-side of the embroidery, and more.
