Information: - Bangiophyceae was a class of red algae ; it has since been merged with the Floridophyceae to form the Rhodophyceae . The Bangiophyceae , as defined traditionally , are paraphyletic . Their taxonomic identification has been difficult because of a lack of distinct morphological features , and the presumed morphological plasticity of the species . Molecular tools are required to elucidate the relationships within this assemblage . It is still used by some sources , and defined sensu stricto ( including Bangia and Porphyra but not the species included in Florideophyceae ) is considered a valid clade . - The red algae, or Rhodophyta (or ; from Ancient Greek: "rhodon", "rose" and "phyton", "plant"), are one of the oldest groups of eukaryotic algae. The Rhodophyta also contains one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority of species (6,793) are found in the Florideophyceae (class), and consist of mostly multicellular, marine algae, including many notable seaweeds. Approximately 5% of the red algae occur in freshwater environments. - Algae (singular "alga" ) is an informal term for a large, diverse group of photosynthetic organisms which are not necessarily closely related, and is thus polyphyletic. Included organisms range from unicellular genera, such as "Chlorella" and the diatoms, to multicellular forms, such as the giant kelp, a large brown alga which may grow up to 50m in length. Most are aquatic and autotrophic and lack many of the distinct cell and tissue types, such as stomata, xylem, and phloem, which are found in land plants. The largest and most complex marine algae are called seaweeds, while the most complex freshwater forms are the Charophyta, a division of green algae which includes, for example, "Spirogyra" and the stoneworts. What is the relationship between 'bangiophyceae' and 'rhodophyta'?
A:
parent taxon