2. Botanical Description Other members of the onion genus, Allium, include A. cepa (onion), A. schoenoprasum (chives), A. ascalonicum (shallots), and A. porrum (leeks). Allium sativum is further divided into two subspecies, A. sativum var. sativum, also known as softneck garlic, and Allium sativum var. ophioscorodon, also known as hardneck garlic. Both varieties are composed of an underground bulb made up of cloves, which are prophylls enclosed by dry membranous skins and held together by a basal plate. The variations differ in that hard neck garlic’s bulb is composed of six to eleven cloves, circled around a centralized woody stalk. This variety of garlic has a scape that curls at the top, but it is generally removed after it curls one to three times. This is because if it continues to grow, less energy can be utilized towards the bulb. Eventually, the scape would give rise to bulbils, containing miniature cloves. The bulbils are occasionally accompanied by white or light purple flowers, although these are sterile. Softneck garlic does not have a flowering top and contains up to twenty-four cloves per bulb. The stem is central and soft, hence the name, and the cloves are layered with larger ones on the outside. Allium sativum is the more common variation, many studies involving garlic do not specify which subspecies is used, but chemical and biological action are assumed to be similar. Allium sativum is sterile and hence is grown asexually from cloves, not requiring a pollinator. It grows best in mild climates, through hardneck varieties are better adapted to colder environments. Allium sativum is a perennial species, as are most members of the genus. Garlic is composed of very strong organosulfur compounds that serve as secondary metabolites as described in the section entitled chemistry and pharmacology. These compounds are responsible for the very pungent smell and taste of raw garlic and act as defenses against predators (Block 2010).
2.1 Bulb Rounded, composed of up to about 15 smaller bulblets known as cloves. Cloves and bulbs are covered by a whitish or pinkish tunic (papery coat).
2.2 Leaves Four to twelve long, sword-shaped leaves attached to an underground stem.
2.3 Flowers Borne in a dense, spherical cluster on a spike (flower stalk) up to 25 cm long. The young flower head is enclosed in a long-beaked pair of enclosing bracts, which become papery and split to reveal the flowers. Individual flower stalks arise from a common point. Flowers are greenish-white or pinkish with six perianth segments (sepals and petals) about 3 mm long. Bulbils (asexual propagules), which resemble tiny cloves, are often interspersed among the flowers.
2.4 Fruits Flowers usually abort before developing to a stage at which fertilization could take place. 2.5 Seeds Not usually produced in the wild but have been produced under laboratory conditions. With a black coat, similar to onion seeds, but approximately half the size.