Sand leek. According to garlic grower Ron Engeland, sand leeks are edible but seldom cultivated, and have a shorter flower stalk and fewer and more inconsistently shaped cloves than Rocambole garlic with which they are often confused. Sand leeks also have a dark violet bulb wrapper. On the other hand, I think this might actually be Rocambole garlic,which is a hardneck variety of garlic.
