When I ask my sim to take a cutting of the toxic chamomile or toxic morel plant, they will take the cutting. And when I ask them to graft one of those cutting onto another plant, it will do the animation and reset the growth state to sprouted (for the plant that was grafted onto). But that plant will not become a spliced plant with both the original plant + toxic chamomile/morel.
Same issue if I try to take a cutting from a different plant and graft it onto toxic chamomile/morel. The toxic plant growth states goes down to sprouted but does not become a spliced plant. This might apply to other OR plants as well. I don't have them all.
(it seems like toxic morel can be grafted with poison fireleaf, but nothing else)
Maybe it's intentional for these to not be able to be grafted (I know that other mushrooms can't be grafted), but if so it would be nice if they didn't have the "graft" option when selected.
