Important Characteristics of Red Algae: Red Algae are an ancient group of algae with over 5,000 living species. Majority of them are marine. A few (example- Batrachospermum, Lemnaea) are freshwater aquatic or subaquatic terrestrial (example- Porphyridium). Their size varies from unicellular microscopic forms to half a metre in length. Several species of red algae are graceful