Next time you drive by it, check and see if it has small leaves in groups of three. If so, it is trifoliate orange -- also known as hardy orange. The scientific name is Poncirus trifoliata. It isn't native, but it is perfectly hardy in this region.

That was my first thought too. We have a small Poncirus Trifoliata growing at our place. There is a much larger speciman growing at the UT trial gardens. It definetaly has some serious thorns on it, and I believe the branches contort a also. Pretty cool its growing wild on the road side.

Doug

Sounds like an old homestead situation.

Doug -- there are two versions of Poncirus trifoliata. The "normal" one is not contorted. There is also a contorted version, referred to as "Flying Dragon".

Incidentally, the little oranges are edible -- if you use lots of sugar! They are occasionally used for preserves.

'Edible'? Maybe.
Most I've encountered have this really nasty oil in the rind that pretty well precludes their use as an edible fruit - but I had a friend send some he'd found at an old homestead in MS that had thinner rind - and less oil - than those I've encountered growing up here in KY - and while it still had minimal pulp and LOTS of seeds, I guess I could call it edible - but it's still something of a stretch.
Most P.trifoliata comes 'true' from seed - so, for instance, if you get fruits from the contorted 'Flying Dragon' selection, its seedlings will display the same contorted growth habit and curved thorns.

It's thanks to Lucky that I have my oranges to play with -- and thanks to him that some of y'all got your very own orange seedlings at the fall swap! Thanks Lucky!

Hey, I just found this quote from Dirr himself!

"Michael Dirr, in his Manual of Woody Landscape Plants, however, comments that "Ripe fruits set aside for several weeks become juicy and develop a sprightly, slightly acid flavor. Serves as a substitute for lemon, pulp can be made into marmalade, and peel can be candied. After removing the numerous seeds there is not a whole lot of pulp left over." "

http://www.tripplebrookfarm.com/iplants/Poncirus.html

You're making me wish I hadn't killed my Calamondin orange. But I did. Not sure why it died, really. Anyone else grow Calamondin? Eating the fruits of that was like eating the candy "Atomic Warheads" or "Cry Baby". Tasty but TANGY.

Thanks folks we now have seed for a Flying Dragon.
Norm