the Bulbasaur is a reptilian creature resembling a toad or dinosaur. it gets its name by being the first pokemon seen with a large bulb on its back, and untill recent events was thought to be apart of the creature. the bulb is achually a symbiotic flower that is called Venus Rafflesia. the Venus Rafflesia is a some what parasitic plant that latched itself onto a passer-by animal and some how conjoines with the animal and gets nutriunts from its host's blood, and in return it provides protection and food. the ways it protects are it lashes out at predators with vines, on the vines are very fine hairs that allow the plant to know when somethins near. and the way it provides food is the smell that it emits attracks prey to the bulbasaur.
but the Venus Rafflesia is attaching itself to other pokemon to but the bulbasaur seems to do the best, because they have the strength to carry it, other pokemon died do to over welming themselves or being slowed down and hunted.