Probably more likely it was an orange tree (or some citrus variety) where the grafted scionwood died, and all that was left was the rootstock, which was probably sour orange (which was a commonly used rootstock back in the 50's.)

Patty S.

You are probably right Patty. Now that I think about it there was an old peach tree there as well.

Randy

If it grew from an orange seed thrown on the ground, we would assume the orange was a sweet orange; and the tree that grew from that seed would likely be a sweet orange.

It's probably poncirus trifoliata if it's like the ones I saw in East Tennessee in the 70's. Mostly thorns, relatively few leaves that come in threes, perfumed sort of fuzzy fruit. Lovely thing. Will grow as far north as Philly or even further if sheltered. Here's a link:
http://www.eattheweeds.com/hardy-orange/

Trifoliate leaves are very small, and the fruit is about 1" diameter and loaded with seeds. That pic on your link is just about life-sized.

Sour orange is still used as a rootstock, and it isn't trifoliate, but a large orange that's sour.