Vintage Black Dress with Buttons and Flowers

Vintage black dress Not sure the era Only tag is the ILGWU (International Ladies’ Garment Workers’ Union) with AFL CIO, so it’s from 1959, when the union’s label was established, or later Estimated size is Medium: this dress is supposed to hang off the body and be a little flowy. Would probably fit a large and be less flowy. Long sleeves with buttoned cuffs. Only one cuff has a button Semi-transparent Fabric pattern is a black background with purple/pink flowers Pintucked creases and pleats down the front Button closure the whole length of the back, all back buttons present Snaps around the inner collar lead me to believe that either a slip or a collar fastened onto the dress. Probably a slip, as the dress is somewhat sheer. Slightly puffed sleeves at the shoulder Please examine photos and video carefully. Thank you.