Mandarin orange, Citrus reticulata, and nuts are some of the more traditional goodies for Christmas stockings. In Northern Europe centuries ago, nuts from the Americas were still exotic treats. The availability of perishable citrus fruits from Mediterranean regions relied on expensively efficient shipping. Consequently, citrus fruits were almost like delicacies.
Even when shipping was slow, Mandarin oranges ripened in time to arrive by Christmas. However, they needed fast shipping because they are more perishable than other citrus. They are innately more prone to oxidation because their rind and segments fit so loosely together. Of course, that is why they are so delightfully easy to peel, pull apart and share.
Mandarin oranges are smaller, more oblate, brighter orange, but also more variable than common sweet oranges. Among their many cultivars, their smaller leaves and thorniness are likewise variable. Very few very old trees grow taller than fifteen feet. Tangerines are merely barely genetically distinct Mandarin oranges that developed within the Americas.