Alga (Biology Glossary)

Alga : (pl.) algae Any member of a diverse polyphyletic group of photosynthetic, eukaryotic, mostly aquatic organisms ranging from simple unicellular microalgae to massive colonial or multicellular forms such as kelp. Algae may reproduce sexually or asexually, and are often compared to plants, though they lack most of the complex cell and tissue types that characterize true plants.