Definition
The *order Ulvales* comprises a group of green algae within the class Ulvophyceae. These are predominantly marine algae, with fewer species found in freshwater. They are characterized by relatively simple thallus structures, such as flattened sheets or tubular filaments. *Order Ulvales* algae reproduce both sexually and asexually. A common example is sea lettuce (*Ulva*). Think of them as a group of simple, mostly marine green algae. They demonstrate algal diversity.