On reeflex you will find not only descriptions of tropical anemones well-known to almost every saltwater aquarist, but also of many cool water species which are as colourful as their relatives in the tropical seas.
Sea anemones can reproduce sexually or asexually. When reproducing sexually the anemones release their eggs and sperm into the open water where the fertilization takes place. Sexual reproduction creates offspring with different DNA than their parents providing them with a more favourable genetic mixture. Asexual reproduction is when one anemone splits into two individuals or buds off parts to form a new anemone. Asexually reproduced anemones are genetically identical twins of their parent. The DNA of these clones remains unchanged from generation to generation.
According to Professor Dr. Dirk Schories there are anemone species along the Chilean coast which over an area of 10,76 sq. ft. (1 m²) have grown into a colony of 30.000 individuals by asexual reproduction.
More details on the different reproduction strategies and on some anemone species of the North-West coast of North America you may find here: