Physical Features
Tree Size: Medium.
Tree Characteristics: Vigorous upright growth habit. Thorny. Long, dark green leaves taper to a point.
Fruit Size: Medium. Flatter than a sweet orange.
Fruit Color: Deep orange with rough, loosely adherent rind.

Sicko Department
Ease of Peeling: Good.
Seeds: Variable.
Holds on Tree: Excellent.
Flavor and Juiciness: Juicy and sour.

The Seville orange is probably the most historically respected orange variety. When the Moors came to Spain, they planted the Seville orange trees in their gardens and mosque courtyards. Beautiful examples of their gardens can be found at La Mezquite (mosque) and the gardens of the Alcázar de los Reyes Cristianos in Cordoba and Patio de Los Naranjos (formerly part of a mosque, but now it's atattched to the Cathedral). The garden within the courtyard wall at La Mezquite in Cordoba is the oldest walled garden in Europe and dates from the 8th century. El Patio de Los Naranjos is the oldest garden in the city of Sevilla. The streets of Sevilla are also ornamented by orange trees and the scent of orange flowers in bloom positively permeates the air.
The Seville orange is one of the "sour oranges" that has developed a sour taste as a DEFENSE MECHANISM!! The oranges and the mother-tree are seldom separated before their parting-time because many people find their distinctive flavor unpleasant. Obviously these oranges desire to be left alone and are so completely adverse to the idea to feeding humans that they have gone so far as to change themselves and become unpalatable.