Varieties include:
Navel: Seedless with navel-like formation at the blossom end of the fruit.
Valencia: Have a juicy, sweet flavour, contain some seeds and thinner peel.
Seville: High acid orange, only suitable for marmalade and glazes.
Blood orange: Has deep red flesh.

Selection:
Choose firm, heavy, glossy fruit. Avoid soft spots.

Storage:
Store at room temperature or covered under refrigeration.

Preparation:
To segment an orange, cut the pith from the orange and run the knife between the membranes of each segment. Do this over a bowl to catch the juice. The outer peel, or zest has a very concentrated orange flavour. If using, remove from the pith carefully with a zester or grater. 

Serving suggestion:
Combine peeled sliced oranges with green skinned apple slices and lots of chopped mint and chives. Make a dressing of equal quantities of orange and lemon juice and little honey and ground black pepper whish in a little sesame oil to taste. Toss gently.
Add fresh orange juice to chicken stock while cooking giving a delicious tangy flavour.