When does Bulbasaur evolve?

Bulbasaur evolves at level 16 and becomes Ivsaur. This line of Pokémon has two more evolutions, one at level 32 into Venasaur and then to Mega-Venasaur by using a mega stone.

Through all of its evolutions, Bulbasaur keeps its grass and poison type, though Poison Powder is the only poison attack it learns. However, it can learn many more moves in later levels, such as Take Down and Growth. It is also part of a group of Pokémon that have mega-evolutions. Mega evolutions are different from normal ones in that a Pokémon can only mega-evolve in battle and must hold its specific mega stone to do so. It must also be fully evolved for its mega-evolution to work.