Probably not Pokemon

[x0_000]

Interesting ideas, I like the potted plant concept in particular. The second form is a bit of a cop-out, though, the only major difference is the number of leaves on the head. Even doing something like adding a tail or making the legs green would spice things up, add more of a "this is the middle of an evolution chain" feeling. Have you considered changing up the pot design as it evolves as well?

For the final evolution of the first line (seahorse?), I assume the far leg shouldn't be a stark blue/black, you should fix that up.