Branch Stitch and its variants.
We embroider several flat stitches vertically (4 or 6), and then we group them in their centre with another flat (smaller) horizontal Stitch.
We can vary this Stitch by making three laces between one stitch and another. The middle lace should be longer than the upper and lower laces. We can also embroider these laces using a different coloured thread to achieve a better contrast.