This pretty handkerchief edging is found in the J&P Coats booklet no 229.
The booklet, copyright 1946 by The Spool Cotton Company of New York contains many traditional patterns by unknown designers and is unfortunately out of print, but occasional copies do pop up on eBay and with second hand sellers.
Copyright: 1946
Designed By: unknown
In looking at these edgings, I’m noticing different methods for attaching. This one looks like a thread was buried in the hem and the picots handled by having the needle emerge and then caught. Or am I missing something?
I thought it was just stitched to the original but I think you may be right about the buried thread