Planktonic – The type that changes the water color. Usually green (pea soup) or brown or even red.
Filamentous – The type that is mat forming. Prior to forming surface mats it may appear as stringy strands beneath the surface often attached to dock legs, plants and rocks.
Branched – The type that looks similar to a plant. Branched or Chara type algae generally grows densely along the bottom suppressing most other growth. See the descriptions below.