Cotton, and why the staple matters
Seersucker is made by holding some warp threads tight and letting others run slack on the same loom. The slack threads bunch, and the pucker is permanent because it is structural, not pressed in.
The fabric
Seersucker
A puckered stripe, woven in. It only touches your skin in places, which is the whole idea.
Air between you and the cloth
Because the surface is raised in bands, only part of it rests against you. Air moves through the gaps. It is the reason seersucker was a summer fabric long before air conditioning.
Never needs ironing
Ironing would flatten the pucker and undo the fabric. Wash warm, tumble dry low, put it on the bed. It cannot look creased, because it is meant to be.
Questions about this fabric
Will the pucker wash out?
No. It comes from the tension on the loom, not from a finish, so it survives the life of the fabric.
Is it only for summer?
It is at its best in warm weather, but the texture works all year on a bed that already has a quilt or a throw.
Does it feel rough?
No. The raised bands are soft; the texture is in the relief, not in the hand.