Sometimes tall flowers when mined will quickly turn into sunflowers before being dropped.

Sometimes tall flowers when mined will quickly turn into sunflowers before being dropped. (The item dropped is not the sunflower, but instead the flower you originally mined

I have tested all tall flowers and I have found that every tall flower has about a 20% chance of quickly turning into a sunflower when mined before being dropped. I only tested in the latest snapshot 14w21b

Here is a video.
https://www.youtube.com/watch?v=D2NJYOmQtlo