Plants doing interesting things

My Fishbone cactus (Epiphyllum Anguliger) has apparently self- fused a new branch into an older one. There is no cut or wound, it just looks like the new growth met the older stem and instead of growing past it, fused into it.


Most interesting, has anyone seen similar behaviour?

 

Its almost a kind of Approach grafting, if you can keep two branches close enough as they grow they will do a natural graft.

Not been there lately but in my local park there is a weeping willow that has two fused branches forming a kind of circle.

I think roots do it as well, but usually we cant see them.