an acid forest humus characterized by an accumulation of organic matter on the soil surface in matted Oe (F) horizons, reflecting the dominant mycogenous decomposers —note 1. the boundary between the organic horizon and the underlying mineral soil is abrupt —note 2. mors may form peat and are sometimes differentiated into the following groups: hemimor, humimor, resimor, lignomor, hydromor, fibrimor, and mesimor —see mullThis definition last updated 07/20/2008