peat

noun

A piece of turf cut for use as a fuel; a mass of partially carbonized plant tissue formed by partial decomposition in water of various plants and especially of mosses of the genus Sphagnum, widely found in many parts of the world, varying in consistency from a turf to a slime used as a fertilizer, as stable litter, as a fuel, and for making charcoal. Peat represents an early stage in the formation of lignite and more bituminous forms of coal, being formed less than 1 million years ago. If dried out, peat will burn, although it produces ammonia fumes. Peat is also cut for use as a soil enricher in horticulture. It is common in Canada, and northern and central Europe, and forms in swampy areas. The decaying organic matter may, in marshlands, emit an inflammable gas (phosphine), whose spontaneous combustion gives rise to the phosphorescent light (ignis fatuus) seen hovering over peaty ground.