I've been helping a Korean woman who was adopted to Norway as a child, but still remembers foraging with her gran and is trying to identify some of the plants so that she can grow them and relive her fond taste memories. This one has me stumped. This is what she wrote:
"Was wondering if you could help me identify a plant from Korea. What I remember regarding this plant are:
The foliage is small and in a rosette. Grows in porous / sandy soils. What is special about this plant is that it is the roots which are edible. The roots are long, even and shiny, and are yellowish white. No side “hairs” on the roots. (almost long like spaghetti but somewhat thicker). There are several long roots on a plant. Do not remember the Korean name unfortunately. The roots do not grow down into the soil, but sideways. It is easy to pull them up. If you find out what it's called, be sure I’ll knit some fine socks for you!!"
I hope someone here recognises the description!