The tree I planted 15 years ago and thought to be sweet orange, turns out to be bitter orange, or some other kind of unidentified-yet citrus... The fruit looks like a hybrid between orange and lemon - orange in colour but with a little lemony "nipple". The flesh itself is more sour than that of lemon and with a peculiar sour-tangerine-like taste.
The best part though, is the scent of it's peel: fragrant and vibrant, somewhat like that of Meyer lemon's, orange and yellow mandarin. Spontaneously, I've decided to use the fruit of my own tree (grown organically, sans pesticide, herbicides, etc.) to be used in my next version of Immortelle l'Amour tea.