The root system is part of the plant that normally grows underground and provides anchorage for the plant, absorption of water and minerals, and storage for foodstuffs. Monocot plants such as lilies, orchids, palms, irises, and grasses are supplied with an extensive fibrous root system. Although a primary root initially emerges from a seedling, it remains just long enough to establish a foothold and is quickly replaced by the outgrowth of many slender roots. Spreading from the stem, the strong fibers are nearly equal in size and continue to form numerous smaller root branches. As do other root structures, this diffuse fibrous network helps to promote terrain stability and prevent topsoil from being warn away by erosion.