From a Worcester Allotment: About garlic

Garlic, Allium sativum, is a species in the onion family Alliaceae.
Its close relatives include the onion, shallot, leek, scallion, chive, and rakkyo.
Garlic has been used throughout history for both culinary and medicinal purposes.
The garlic plant's bulb is the most commonly used part of the plant.

Know your Garlic - Botany

With the exception of the single clove types, the bulb is divided into numerous fleshy sections called cloves.
The cloves are used for cloning, consumption (raw or cooked), or for medicinal purposes, and have a characteristic pungent, spicy flavour that mellows and sweetens considerably with cooking.
Garlic is an upright plant that grows up to about 60 cm tall.
The long, sword-shaped leaves grow from the bulb beneath the surface of the soil.
The bulbs are rounded, composed of several smaller bulbs called cloves.
Cloves and bulbs are covered by a white papery coat and are used in both cookery and medicine.

Only known as a domesticated crop in cultivation, it is not known which species was the originator.
The word garlic comes from Old English garleac, meaning "spear leek."
Dating back over 6,000 years, it is native to Central Asia, and has long been a staple in the Mediterranean region, as well as a frequent seasoning in Asia, Africa, and Europe.
Egyptians worshiped garlic and placed clay models of garlic bulbs in the tomb of Tutankhamen.
Garlic was so highly-prized, it was even used as currency.
Folklore holds that garlic repelled vampires, protected against the Evil Eye, and warded off jealous nymphs said to terrorize pregnant women and engaged maidens.
And let us not forget to mention the alleged aphrodisiacal powers of garlic which have been extolled through the ages.

The leaves, and flowers on the head (spathe) are also edible, and being milder in flavour than the bulbs, they are most often consumed while immature and still tender.
Additionally, the immature flower stalks (scapes) of the hardneck types are sometimes marketed for uses similar to asparagus in stir-fries.
The papery, protective layers of "skin" over various parts of the plant are generally discarded during preparation for most culinary uses, though in Korea immature whole heads are sometimes prepared with the tender skins intact.
The root cluster attached to the basal plate of the bulb is the only part not typically considered palatable in any form.

The sticky juice within the bulb cloves is used as an adhesive in mending glass and china.