I found this pattern at https://www.youtube.com/watch?v=TRUWvjHfe78 unfortunate it is in spanish wich I don't understand. I have therefore made an interpretation of the pattarn here.
start with 54 chain stitches and make 1 double crochet in the fourth chain from the hook and continue with one double crochet in each chain stitch.
Now you turn the work and chain 3 and in the same stich make three double crochets. in the next stitch make one half crochet. Then continue with *four dc in one stitch and then one hdc in the next* this is repeated the hole length.
Watch how she sew it together at the youtube clip. Than make the leaf. This is how I have made mine.