Root systems of various different plants. Ivy (Hedera helix), at bottom, can be seen with roots coming from the nodes of the trailing stem (adventitious roots). Also seen (on the left-hand side), from left to right, are the parsnip (Pastinaca sativa, yellow), the dandelion (Taraxacum sp.) and the carrot (Daucus carota). These three plants exhibit taproots, tapering roots that grow vertically downwards and are often modified to become storage organs. On the right-hand side, from left to right, are grass, broad-leaved plantain (Plantago major) and the onion (Allium sp.). In these the primary root withers and is replaced with a large number of fine roots, which are mainly confined to the surface of the soil (a fibrous root system).