Re: What are the differences b/w clementines, tangerines, satsumas & mandarins

Tangerine, Satsuma orange and mandarin orange are common names for the species 
Citrus reticulata. Mandarin orange is the preferred common name according to 
Hortus Third. 'Clementine' is a cultivar (cultivated variety) of Citrus 
reticulata. Satsuma orange is also the name of a horticultural class of mandarin 
oranges that are the most cold hardy of commercial citrus. The horticultural 
class, Satsuma orange, includes several cultivars of Citrus reticulata.

Wyman (1986) notes that tangerines tend to be smaller than Satsumas with orange 
skin and flesh. Satsumas tend to be larger than tangerines with yellower skin 
and flesh.

References

Bailey, L.H. et al. 1976. Hortus Third. New York: Macmillan.

Wyman, D. 1986. Wyman's Gardening Encyclopedia. New York: Macmillan.