An ear is the grain-bearing tip part of the stem of a cereal plant, such as wheat or maize. It can also refer to "a prominent lobe in some leaves". The ear is a spike, consisting of a central stem on which grows tightly packed rows of flowers. These develop into fruits containing the edible seeds. In corn, it is protected by leaves called husks. In some species (including wheat), unripe ears contribute significantly to photosynthesis, in addition to the leaves lower down the plant. A parasite known as Anguina tritici (Ear Cockle) specifically affects the ears on wheat and rye by destroying the tissues and stems during growth. With exception to North Africa and West Asia, the parasite has been eradicated in all countries by using the crop rotation system.