From Bulbapedia, the community-driven Pokémon encyclopedia.

Bayleef is a species of Pokémon. It may also refer to specific Pokémon of that species:

• A Pokémon which belongs to Ash Ketchum: Ash's Bayleef
• A Pokémon which belonged to Casey before evolving: Casey's Bayleef
• A Pokémon which belonged to Vincent before evolving: Vincent's Bayleef