Explanation

Sea anemones are called flower animals because they look like flowers. 

They are marine animals that are part of the class Anthozoa, which means "flower animals" in ancient Greek.

They are cylindrical in shape.

They are attached to a substrate.

They are often brightly colored.

They can grow to be 1.8 to 10 cm in diameter.

The name "anemone" comes from the anemone flower.