The Slat Bonnet is named after the “slats” used to stiffen its’ brim. Originally these slats were made from hickory or cedar. This bonnet was often worn by those who were working in the fields or around the homestead. The deep brim and long bavolet (curtain at the back) protected the face and neck from the harsh elements. This style bonnet was very seldom worn “for good”. Source for patterns: Timeless Stitches
This print is for sale on ebay, listed as a CDV photograph, but looks like artwork to me.
“This pattern is for a moderate slat bonnet, one that reasonably covers the face from cheek to cheek and a curtain that extends just to the shoulder. Ties at the back are used to shape the bonnet.” Source: Timeless Stitches tstitches.com