“ When you sleep, your soul briefly returns to the place where it was created/goes to when it dies, and seeks nourishment. Everybody's soul is created with a little link (or you could say a greater entity calls it back) to that place so that it can return easily, but upon death, the soul returns via that and annihilates the link as if returns.
Also, as an added thingy, you could say the entity supplying the link, or residue of the links themselves, (whichever) is the source of all arcane power.”
“ Plant that is likely to produce allergic reactions in almost everybody, even by touch. Usage: medicinal, in very exotic foods, non-lethal traps, disabling opponents (have you ever cut an onion,anyway?), spell components, etc.”
“ Giant mushrooms the size of trees. The stems and parts of the caps can be used in construction, and only the gills are soft enough to eat. An entire fungi-forest can grow in a matter of days, provided the correct conditions. Most fungus trees last about a month before collapsing, but not before a new generation sprouts to provide shade for the next spores.”