The mod/item is an add-on(by another mod) for ThaumCraft.
- "[...] You're done squid hunting. By infusing a rose with tenebrae and victus, you
- create a flower that spreads like a weed and those petals can be crushed for ink" - Part of its Thaumonomicon Entry
The Umbral Rose is a useful way of obtaining ink sacs (other than killing squids). It is added by Forbidden Magic, a Thaumcraft Add-On.
It'll spread very quickly on grass and each flower can be crafted into 2 inc sacs.