Garlic is an herb that is grown around the world. It is related to onion, leeks, and chives. It is thought that garlic is native to Siberia, but spread to other parts of the world over 5000 years ago. Garlic is most commonly used for conditions related to the heart and blood system. Allium sativum is a perennial flowering plant growing from a bulb it has a tall, erect flowering stem that grows up to 1 m (3 ft). The leaf blade is flat, linear, solid, and approximately 1.25–2.5 cm (0.5–1.0 in) wide, with an acute apex. The plant may produce pink to purple flowers from July to September in the Northern Hemisphere. The bulb is odoriferous and contains outer layers of thin sheathing leaves surrounding an inner sheath that encloses the clove. Often the bulb contains 10 to 20 cloves that are asymmetric in shape, except for those closest to the center If garlic is planted at the proper time and depth, it can be grown as far north as Alaska. It produces hermaphrodite flowers. It is pollinated by bees, butterflies, moths, and other insects. Identification of the wild progenitor of common garlic is difficult due to the sterility of its many cultivars, which limits the ability to cross test with wild relatives. Genetically and morphologically, garlic is most similar to the wild species Allium longicuspis, which grows in central and southwestern Asia. However, because Allium longicuspis is also mostly sterile, it is doubtful that it is the ancestor of Allium sativumOther candidates that have been suggested include Allium tuncelianum, Allium macrochaetum and Allium truncatum, all of which are native to the Middle East.