In this case “parallel” is: > First, what is a tree? It’s a big long-lived self-supporting plant with leaves and wood. That is such a broad thing that it's ha

In this case “parallel” is: > First, what is a tree? It’s a big long-lived self-supporting plant with leaves and wood. That is such a broad thing that it's hardly remarkable. I find carcinization, or independent evolution of eyeballs from completely different tissues to be more remarkable. This is no more remarkable than that animals independently evolved to be large, and in doing so evolved different hard support structures to support this, which for instance worms lack.