If you add bone meal to small dripleaf stems that are in two block high water, and keep adding bone meal to the highest waterlogged stem, water source blocks will appear in parts of the stem, and will keep appearing when you bone meal the waterlogged stem blocks. 

How to Reproduce:

1. Put a small dripleaf stem in two-block high water and add bone meal to it.
2. Keep adding bone meal to the stem that is right below the surface until a water source block appears on the stem.
3. Add bone meal to waterlogged stem blocks on the stem until more appear.