Algae are very primitive plants. Some algae are microscopic (Planktonic algae), others are thin and stringy or hair-like (Filamentous Algae), while still others are large and resemble higher plants but without true roots (chara).
Chara
Chara is often called muskgrass or skunkweed because of its foul, musty, almost garlic-like or skunk odor. Chara is a gray-green branched multicellular algae that is often confused with submerged flowering plants. However, Chara has no flower, will not extend above the water surface, and often has a “grainy” or “crunchy” texture. Chara has cylindrical, whorled branches with 6 to 16 branchlets around each node.
Chlamydomonas, Chlorella, Euglena, Closterium, Planktonic Algae, etc.
Planktonic algae are floating microscope plants that are normal and essential inhabitants of sunlit surface waters. There are literally millions of floating planktonic algae and these color pond water shades of green, blue-green, brown or variations in between. Planktonic algae that color the water is often called a “bloom” or “algae bloom”. Many species of algae are involved in algae blooms and these species change over time based on temperature, light, nutrients, and other factors.
Spirogyra, Anabaena, Oscillatoria, Lyngbya, Pithophora, etc.
Filamentous algae are single algae cells that form long visible chains, threads, or filaments. These filaments intertwine forming a mat that resembles wet wool. Filamentous algae starts growing along the bottom in shallow water or attached to structures in the water (like rocks or other aquatic plants). Often, filamentous algae floats to the surface forming large mats, which are commonly referred to as “Pond scum.” There are many species of filamentous algae and often more than one species will be present at the same time in the pond.