Garlic Flowers, Scapes and BubilsThere are many garlic varieties, some of which produce genuine flowers. However if you're growing garlic yourself it's unlikely that you will see true flowers.
The most commonly grown variety of garlic is allium sativum. This is divided into two main sub-varieties, hardneck garlic and softneck garlic.
Scapes and Bubils
HardneckHardneck garlics usually form a flower stalk - or scape - at the top of the garlic plant. At the top of the scape grows what is commonly called a garlic "flower".
In fact this is a misnomer, any flower which starts to develop usually aborts (cultivated garlic is sterile - the plants are technically clones). Instead what is normally seen at the top of the garlic scape is a collection of bubils - miniature cloves.
The scape and bubils can be considered akin to "bolting" in other plants. If the scape and bubils are left in place, the garlic plant will expend energy on growing them that could be better used to grow the bulb. The usual advice is therefore to remove the bubils - if you don't then your garlic crop is likely to be of small size.
SoftneckSoftneck garlics rarely produce scapes and bubils which is one of the reasons they are considered easier to cultivate, especially on a large scale.