Lemna is a type of aquatic plant that is sometimes referred to as duckweed. There are several synonyms for this word, including water lentil, bayroot, and watermeal. Water lentil is an appropriate name for lemna, as it is a tiny plant that floats on the surface of water, resembling a small lentil. Bayroot is another fitting synonym, as the plant is often found in sheltered bays and coves. Watermeal is also an accurate description, as the plant is so small that it can resemble tiny specks of meal floating on the surface of water. Regardless of what you call it, lemna is an important part of many freshwater ecosystems.