Short, thickened, mostly underground stem that constitutes the resting stage of certain seed plants. It is often an organ of food storage, reproduction, or both. It bears minute scale leaves, each with a bud that has the potential for developing into a new plant. The common potato is a typical tuber; the much-reduced leaves and associated buds form its eyes. The term is also used imprecisely but widely for fleshy roots or rhizomes that resemble tubers (e.g., the tuber of the dahlia, actually a tuberous root).