 A number of microscopic algae also occur as symbionts in lichens.Phycologists typically focus on either freshwater or ocean algae, and further within those areas, either diatoms or soft algae.While both the ancient Greeks and Romans knew of algae, and the ancient Chinese even cultivated certain varieties as food, the scientific study of algae began in the late 18th century with the description and naming of "Fucus maximus" (now "Ecklonia maxima") in 1757 by Pehr Osbeck.