Fruit type of sunflower is

The fruit type of sunflower is Cypsela.
Cypsela is a dry single-seeded fruit formed from a double ovary of which only one develops into a seed, as in the daisy family.
The term "sunflower seed" is a misnomer when applied to the seed in its pericarp (hull). Botanically speaking, it is a cypsela. When dehulled, the edible remainder is called the sunflower kernel or heart.