I tend to forget about plants more than I have them come back from the grave. I found a decent sized compact sword under a bunch of other plants awhile back. I had no idea it was still in there, being one of the original plants I got when I had first set that tank up 3 years prior. As soon as it was exposed, I got a shoot from it that went out of the tank and bloomed.
Plants are like otos to me. In some tanks I'll find an oto in there and it'll surprise the heck out of me because I had no idea I had any in there. Kind of a " What the @#$?? When did I put these in there?" type of thing.
I don't ever remember having riccia in my 75 gallon, but I keep finding it regardless. It might have come from the huge wad of it I found in a shrimp tank, which I also did not put there. I've never ordered, traded, or otherwise received riccia on purpose, lol.
"Good judgment is the result of experience, experience is the result of bad judgment." --Mark Twain