Diamond root

From Wikimalia

Herbalism Resource
Diamond Root Habitat: Description: This plant appears quite simple, with small yellow or orange flowers. Its deep green leaves are heart-shaped, quite broad, and boast deep purple veins. The root is the more remarkable part, a thick, meaty tuber that possesses an incredibly tough skin that only hardens as it dries. Usages: Notes:

Hirithel's Guide to Edible Plants

Diamond root is a remarkable plant for cuisine. The plant's above-ground structures serve mostly to feed its roots, which dry to have a hard shell (hence, the name) The soft, white meat inside the shell emits a rich, sweet aroma that only hints at its incredible taste. But don't think that since the roots are so delicious that the flowers might be as well. While they are not poisonous, only the most bizarre of palates is at ease with their extremely bitter flavor.