Leaf stitch (surface)
Leaf stitch is a series of overlapping open diagonal stitches. It is easily adapted to forms of varying width, such as petals and leaves.
Method
Imagine or faintly draw a double stem line. Starting at the base of your shape bring your needle up through the fabric on one of the stem lines.
Take the needle to the opposite side of the shape and take it down through the fabric on the line, creating a straight slanted stitch.
Do the same on the opposite side by bringing the needle up through the fabric on the other stem line just under the previous stitch and taking it down on the opposite side of the leaf.
Repeat the process, bringing the needle up just under the previous stitch and above the rest.
Continue by working up towards the tip of the shape until it is filled.

Structure of stitch
Embroidery Techniques
Related Stitches
References
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Mary Thomas’s Dictionary of Embroidery Stitches (1934) , p.144–5