In terms of its morphology, the onion has a root system formed by numerous fasciculate, whitish, shallow rootlets that emerge from a disk-like stem or caulinar disk. This caulinar disc presents numerous knots and internodes (very short), and from this leave the leaves. The leaves have two clearly differentiated parts: a basal, formed by foliated sheaths as a consequence of the accumulation of reserve substances, and another terminal, formed by the filodium, which is the green and photosynthetically active part of the plant. The thickened leaf pods form the "tunics" of the bulb, the outermost being of a parchment-like nature and having a protective function, giving the bulb the characteristic color of the variety. The phyllodes show the welded leaf margins, giving a hollow leaf appearance. The leaves are arranged alternately.