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Washington State Department of Ecology > Water & shorelines > Freshwater studies > Lake water quality > Aquatic Plant Guide > Plant Categories


Aquatic Plant Identification Manual for Washington's Freshwater Plants

Plant Categories

We divide aquatic plants into seven categories based on their habitat type and growth form. We also describe an eighth category of non-plant organisms (or "curiosities") that are often seen in Washington lakes. The icons for each category are shown next to each category description. 

Click on the icon or title to see the list of plants in each category.

Shoreline Plants Icon
Shoreline Plants grow along edges of lakes, rivers, streams, and ponds or on wet ground away from open water. They have at least part of their stems, leaves, and flowers emerging above the water surface and are rooted in the sediments. Some plants that typically grow in deep water may be found along the shoreline in late summer when water levels are low.
Foating Leaved Root Plants Icon Floating Leaved Rooted Plants are rooted in the sediment and have leaves that float on the water surface. They may also have underwater leaves. Often the stems of these plants are not firm enough to keep them upright when removed from the water and at low water they may be found collapsed on the lake bottom. They often form a band along a lake margin in water one to three meters deep.
Floating Mat Rooted Plants Icon Floating Mat Rooted Plants typically grow in a tangled mass of stems, leaves, and flowers that form a mat on and above the surface of the water. They are generally rooted in the sediment and may have underwater leaves. They are usually found near the shoreline in water less than one meter deep.
Free Floating Plant Icon Free Floating Plants float in the water column, on the surface of the water, or lie on the bottom. This category includes some of the smallest members of the plant kingdom such as watermeal plants, which look like green specks on the water surface. These plants do not root in the sediment, although some species have roots that dangle in the water. They sometimes form extensive green mats on the water surface. 
Submersed Plant Icon Submersed Plants are usually found entirely underwater, but the flowers and fruits may rise above the water surface. Submersed species are rooted in the sediment and have underwater leaves. They can grow from shallow water to depths greater than ten meters in very clear water. 
Plant-Like Algae Icon Plant-Like Algae lack stems and leaves, although sometimes they have structures that can be mistaken for stems and leaves. Plant-like algae are green with cylindrical, whorled branches. They lack roots, but some species attach to the sediment. Plant-like algae tend to lie on or just above the sediments. They are found from shallow water to very deep areas (20-30 meters) in clear water. 
Aquatic Moss Icon Aquatic Mosses are small plants with delicate stems and small closely overlapping leaves. These plants can have branched, stem-like, and root-like structures. Unlike most other plants described in the manual, the aquatic mosses never produce flowers. Aquatic mosses are often seen growing attached to rocks in mountain streams, but they also grow in the shallow to moderately deep water of lakes. 
Curiosites Icon Curiosities includes interesting things that may be found in freshwater lakes and rivers. These curiosities include byrozoans and colonial animals, as well as filamentous algae.

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