Stem stitch. A slight variation on the traditional stem stitch, this is a way to form a finer line which works well with this kind of embroidery.
Instead of making the traditional slanted stitches, insert the needle along an imaginary or drawn line as shown. Longer stitches of 1 to 3 cm (3/8 to 1”) are also used for a smoother texture.
Stitch diagram is © Metz Press and Di van Niekerk.