The smallest member of the citrus family, kumquats, like their larger relatives, originated in China. Resembling a tiny oval or round orange, kumquats are the easiest fruit to eat-after a quick rinse, just pop them in your mouth, skin, seeds and all. Kumquats are different from other citrus fruits in that the skin is sweet and the flesh is very tart. Look for firm fruit without blemishes. Kumquats are in season from November through March.