Scratch that last post.... my mother (who made the collar) pointed out to me that I had stretched it too much and that the straight neck edge is actually slightly curved at the ends. So here is the better photo:
You seamstresses are so smart anyway, you probably can work a pattern off the photo!
The ruffle was cut on the bias, 2 inches wide, and 2-3 times as long as the edge to which it is sewn. The ruffle was narrowly hemmed on one side, gathered on the other, and sewn to the edge with 1/4 seam allowance, then a zig-zag stitch over the raw edges to finish. Then the neck edge was narrowly hemmed, including the ends of the ruffle.