Sorry there is not much contrast in the photo - you will have to look closely to see this week's BAS stitch - the Maidenhair Stitch. It is basically a series of feather stitches, however, one arm of the feather stitch is progressively longer in each set. As long as you know the feather stitch, the maidenhair stitch is pretty self explanatory from looking at the photo. I found a good stitch diagram for you at Needcrafter.com - I hope that it is helpful.
Happy stitching and enjoy this week's challenge!