Yucca and Corn fibers

I have heard a rumor that some people used to make spinable fiber out of yucca leaves, and others make fiber out of either corn silks or corn leaves.  Is either rumor true? If so, how would someone go about doing that?

check out this thread:
https://permies.com/wiki/150488/fiber-arts/Twine-Cordage-Yucca

also if you scroll down a ways on the right side you will see a category for fiber arts with more threads of a similar nature