The name "algae" is given to a group of organisms of mixed affinity, but the word itself has no taxonomic significance. Not all algae are even found in the plant kingdom. Most algae do not have vascular tissue, a high level of organ differentiation, or protective layers of cells surrounding their reproductive structures. Most algae do make their own food through photosynthesis although a few algae (such as Euglena ) must locate and engulf their food. The size of algae range from tiny microscopic life to giant ocean kelps and they live in the driest deserts, the coldest tundras, and all types of waters.
At Point Reyes National Seashore most algae are found on rock surfaces, covering the surface of ponds, and laced around the intertidal zone (marine algae).