Modern taxonomies rank the group as a phylum or subphylum.
Forams are abundant all over the ocean. A few benthic species have been recorded from terrestrial environments including ground water. The size of the foraminiferal test typically ranges from 0.05mm to 0.5mm although some forams may be as large as several centimeters with a recorded maximum of 18cm in diameter. Foraminifera remain single-celled despite the large sizes they reach. And this is where the reticulopodia, a highly efficient and multifunctional organelle, come into play.