This is a simple and plain Victorian cotton day cap, such as in this Victorian painting or this 1855 painting. ‘This shape is particularly liked by the poor, from the ease with which it is made up and washed, as, upon undrawing the string, it […] lies quite flat to be ironed.’ (The Workwoman’s Guide, 1840)
It’s made with white cotton batiste.
The day cap is completely handsewn.
It is gathered with a string.
It’s quite easy to iron as it lies perfectly flat, when the back of the cap isn’t gathered.
Here’s a ca. 1865 flat day cap with drawsting casing at the neck, and another similar day cap (apart from the ruffle); and another plain cotton day cap.
Here are close-up pictures of my handsewn day cap.