Algae are a very large and diverse group of eukaryotic organisms, ranging from unicellular such as chlorella , diatoms to multicellular forms giant kelp and a large brown algae grows up to 50 meters of length. There are most of Autotrophic distinct cell and tissue types found in land plants such as stomata, xylem ,phloem and the largest and most complex marine algae are called as seaweeds and the most complex freshwater forms are the charophyta. A division of algae that includes spirogyra and the stoneworts. Algae have chlorophyll as their primary photosynthetic pigment and lack a sterile covering of cells around their reproductive cells. It constitutes a polyphyletic group since they do not include a common ancestor and although their plastids seem to have a single origin from cyanobacteria.
Last date updated on July, 2014