The foundation of a buttonholed bar is made up of three or more threads from the worked area of the ground material. Over these threads is worked the ordinary buttonhole stitch. If a single row of buttonhole stitches is used, then the stitches need to lie closely together. If a double row of buttonhole stitches is used, then the first row is worked with the stitches placed with a gap in between each stitch, then a second row of buttonhole stitches is fitted into the spaces left in the first row. This technique is especially associated with Italian cutwork.
See also: overcast bar.
Source: THOMAS, Mary (1934). Mary Thomas’s Dictionary of Embroidery Stitches, London: Hodder and Stoughton, p. 7.
Digital source of illustration (retrieved 3 June 2016)
GVE