Milkweed or Asclépiade
This is a toxic plant, to be exact the sap/latex is, so waiting to collect until the plant is drying out is a must. Once dry it is safe to touch it. It's good to keep few plants around to help the monarch butterflies as it is their primary feeding, they do lay their eggs on it and the caterpillars will munch on the leaves.
I had few pods left on the dried plants and I wanted to experiment with some of it.
This is how it looks like when you open a pod.
This is what I get once I pulled off the seeds.
The fibers are softer than silk and very light, it's good to work in an area without any drafts or it will fly all over the place. The thermal properties of this fiver are higher than wool and even duvet, so this could be used as filling/insulation.
I have mixed some with some wasted wool and spun a little for a test run.
This could make a wonderful yarn to work as weft weaving, it's lustrous and so soft.
I will have to experiment more but I really like the way it feels.