Flax.

This link - https://www.blipfoto.com/entry/2992107354859767251  shows what the shot above looked like when it was growing.  It was Open Day at the allotments today and I was on the book stall - next to us was the lady whose friend had grown the flax for her.  She explained the process of pulling the plant stems to harvest them,  retting  and scutching.  She makes cordage and had a display board showing examples of some that were extremely fine from all sorts of dried plant material, a craft that has come down from the Stone Age.  3rd from top right on the board in Extra is cordage made from leek plants.  Patterns for garments were cut so that there was no wastage of fabric - see examples from a book she has made and wearing a garment to show the completed article - not made from flax but curtain lining!  
It was another lovely day, warm , sunny. light breeze - perfect for our Open Day - good attendance, lots of lovely people to chat to with a very villagey atmosphere.  Sold quite a few books as the communal library was looking rather full - reduced the stock but not much money from 40p each and three for a pound.