Sunflower

The  is a Flower. It can only be obtained through the Flower Minion, from trading with other players or by using bonemeal on an already planted sunflower.

Flower Minion
The Flower Minion generates different types of flowers, including Sunflowers.

Bone meal
If you use bone meal on the top block of a sunflower, another sunflower will pop off of the original sunflower. This can be useful for obtaining large amounts of sunflowers without having a flower minion.