The Kingdom Protista
This kingdom, sometimes called Protoctista, consists of single-celled microorganisms and simple multicelled organisms.
The protozoans. Single-celled; solitary or in colonies. Aquatic, terrestrial, or parasitic. Examples: amoeba, globigerina, paramecium.
Golden-brown algae, or diatoms, and yellow-green algae. Most are single-celled. Marine and freshwater. Contain chlorophyll.
Fire algae, or dinoflagellates. Most are single-celled; marine. Contain chlorophyll.
Most are single-celled flagellates containing chlorophyll. Freshwater, marine, or parasitic. Example: euglena.
Brown algae. Multicelled; marine. Contain chlorophyll. Example: kelp.
Red algae. Multicelled; most are marine. Contain chlorophyll. Example: Irish moss.
Green algae. Single- and multicelled; most are freshwater. Contain chlorophyll.
The plasmodial slime molds. Body is a thin, flat mass of protoplasm with many nuclei. Certain kinds parasitic.
The cellular slime molds. Body is multicelled and sluglike.
The chytrids. Single-celled. Parasitic or absorb dead organic matter.
White rusts, downy mildews, and water molds. Parasitic or absorb dead organic matter. Some of these organisms have caused serious plant diseases, such as the potato blight in 19th-century Ireland.