Ugli fruit are, despite
bonboard's assertions, not the
product of
breeding a
tangerine with a
grapefruit, but of
breeding a
tangerine with a
pummelo.
That's
why they're called (
Jamaican)
tangelos.
The pummelo is also spelled pomelo, and is an ancestor of the modern grapefruit. Also known as a grape fruit (transliterated) in Chinese, not to be confused with grapefruit.