lilypads won´t spawn on swamp biomes

lilypads won´t spawn on swamp biomes

What I expected to happen was...:
To find lilypads in swamp biomes

What actually happened was...:
there was none lilypads in swamp biomes, and I checked out A LOT of swamps

Steps to Reproduce:
1. no lilypads
2. no lilypads spawning in swamps
3. empty swamps