examples of algae
More than 25,000 species of algae live in aquatic environments or in some regions with damp soil; they vary in size from microscopic to 60 ft in length.
brown alga 
Brown-pigmented alga that usually lives in the sea, often in cold water; there are more than 1,500 species of brown algae.
green alga 
Alga often found in freshwater, but also in seas and some nonaquatic environments; there are 6,000 species of green algae.
red alga 
Red-pigmented alga that generally lives in salt water and at greater depths than other algae; there are 4,000 species of red algae.
hapteron 
Small, occasionally branched disk, located at the base of certain thalli, enabling their attachment to a substrate.
lamina 
Part of the thallus that is shaped like a blade; it is quite wide and looks like a leaf.