This is fiber taken from the kudzu vine. Here in the South kudzu is an invasive plant that can take over entire tracts of land in a season or two. Despite being an invasive weed it is a beautiful lush green against the sometimes dry and burnt colors of late summer. Kudzu flowers give off a thick sweet scent, vines can be woven into baskets, and the fiber from the vines can be woven into fabric.
I took this kudzu fiber back in the fall last year. It is a delicate fiber that has a glossy sheen which I think was part of the reason it was such a desirable fiber for clothing of the upper classes in old Japan. I have it resting here in an Edo era lacquer ware bowl. The bowl has a beautiful uneven shape and thick deep red lacquer. I imagine that it was made by a rural lacquer maker as it has a strong rustic handmade feel rather than the delicateness of a more refined city made bowl. There is a long process of taking kudfu fiber from the vines. Vines are gathered and bound then boiled for about an hour. The bound and boiled rolls of kudzu vines are then left outside to ret under leaves or grasses for a few days. When a powdery white mold appears on the vines and they are slimy to the touch the inner vines can be stripped from the outer fiber. Then the fiber can be washed and scraped to remove the slimy outer coat.
I have only attempted to make kudzu thread but this site http://www.ryukyutextile.com/kasuri/Weavers_studio_4.html is a great visual guide for processing kudzu fiber.