The botanical name of sunflower is:

Systematic Position:

Kingdom: Plantae
Family: Asteraceae
Genus: Helianthus
Key Characteristics:

The sunflower plant has an erect rough-hairy stem, typically growing to heights of up to 3 meters.
It belongs to the Asteraceae family, also known as Compositae, which includes over 32,000 known species in more than 1,900 genera within the Asterales order.
The sunflower has a capitulum inflorescence (a cluster of flowers arranged in a head).
Additional Information:
Common and Botanical Names of Other Plants:

Garden Dahlia: Dahlia pinnata
Mexican Marigold: Tagetes erecta
Zinnia: Zinnia elegans