Definition
Stonewort is a common name for a group of green algae belonging to the order Charales. They're multicellular and resemble submerged plants with stem-like structures and whorls of branches. These algae often have a rough, calcified texture, giving them a "stony" feel. Think of them as the underwater shrubs of freshwater ecosystems. They provide habitat for aquatic invertebrates and help to clarify the water. Stoneworts are like tiny apartment complexes for small aquatic creatures.