Sea Anemones are not flowers

Sea Anemones are present all over the seabed of the Costa del Sol. Most important they are not flowers but look like flowers, in fact they are actually animals. Their “petals” are armlike body parts called tentacles, which circle the mouth. The tentacles may be red, yellow, green, blue, orange, brown, white, or a mixture of colors. They use their tentacles to sting the shrimps, fish, and other small animals that they eat.

Invertebrate

There are more than 1,000 species, or kinds, of sea anemone. They live in oceans throughout the world.

Sea anemones are invertebrates, which means they do not have a backbone. They have soft bodies that may be thick and short or long and slender. Most of the body is made up of water. They range from less than 2.5 centimeters to about 1.5 meter across.

Sea Anemones Habitat

Most sea anemones rarely move. Some glide very slowly or do slow somersaults. They are usually found attached to a hard surface such as a rock, a seashell, or the back of a crab. A flattened disk attaches the animal to an object by suction. On the other hand some ot them float near the ocean’s surface or burrow deep into sand or mud.

This invertebrates are related to jellyfish. Like a jellyfish, a they can sting a person who touches it. 
They are commun on our dives along the Beaches from Sabinillas, Bahía Casares, Estepona, Sotogrande, San Roque, Algeciras and Tarifa. 

More info with wikipedia