A proven early variety that is still very popular today. Excellent colour and flavour; the skin is smooth, glossy, thin and easy to peel. Older trees may develop a biennial bearing habit.
 
Description from The Citrus Industry Vol. 1 (1967):
"Fruit medium-small to medium, oblate to broadly obovate; short basal neck or low collar; apex depressed.  Rind very thin, leathery, smooth and glossy, with slight adherence but no puffing until mature; color yellowish to pale orange at maturity.  Segments 9 to 11, easily separable; axis medium and hollow.  Flavor pleasantly subacid with attractive aroma.  Comparatively few seeds.  Very early in maturity (about like Wase satsuma).  Loses quality if left on tree after maturity. 
      Tree vigorous, medium in size, upright, virtually thornless; leaves long, slender, and taper-pointed.  Some tendency to alternate bearing. 
      Imperial originated about 1890 at Emu Plains, some thirty miles west of Sydney, New South Wales, and is believed to be a chance hybrid of Mediterranean or Willowleaf, to which it bears considerable resemblance, and some other mandarin?possibly Emperor.  Because of its early maturity, attractive appearance, and pleasant flavor, it commands a premium in the markets."