The lady in the green is holding the slip to a Christening gown that has been in her family for several generations. The initials of the children are embroidered on the hem with the date they are christened.
How wonderful! My family has done something similar. All the names and dates of the christenings. My dad and his brothers, my brothers and sister and I and our cousin, and our children. What a treasure this lady's family has. I like the looks of the initials in white thread on the hem of hers.