REd algae
Algae are thought to be the oldest plants on the planet. Red algae falls under the kingdom protista and is in the phylum rhodophyta. They are most commonly found in warm tropical waters around the world. In these tropical waters they are mostly found in deeper points of the water. They are called red algae because of the fact that they are red.
brown algae
Brown algae also falls under the kingdom protista, but falls under the phylum heterokontophyta. They are found mainly in marine and temperate waters. An example of brown algae, that most people know, is kelp.
green algae
Green algae is the most well known as well as the most abundant in the world. You can find green algae everywhere. They are though to be the plant that all other plants developed from. They are part of the phylum chlorophyta and kingdom protista. Green algae comes in three forms, unicellular, colonial and multicellular. These algae live in all kinda of environments. Green algae come in different shapes and forms depending id they are colonized, multicellular, or unicellular.