Ombrotrophic ('cloud-fed'), from Ancient Greek ὄμβρος meaning 'rain' and τροφή meaning 'food'), refers to soils or vegetation which receive all of their water and nutrients from precipitation, rather than from streams or springs. Such environments are hydrologically isolated from the surrounding landscape, and since rain is acidic and very low in nutrients, they are home to organisms tolerant of acidic, low-nutrient environments. The vegetation of ombrotrophic peatlands is often bog, dominated by Sphagnum mosses. The hydrology of these environments are directly related to their climate, as precipitation is the water and nutrient source, and temperatures dictate how quickly water evaporates from these systems.