I came across a citrange tree today with many fruit on the ground. I would like to know which variety it is. The fruit are the size of golf balls or a bit larger. Didn't have a camera with me so no photos, but I collected a bunch of fruit to try as rootstock. Anyone have a idea which variety this might be ?

The five original citranges, produced in the early 1900's, were Rusk, Willetts, Savage, Colman and Morton. See my web-page
http://www.homecitrusgrowers.co.uk/citranges/usdacitranges.html
I checked the size of a golf-ball. It is apparently 42.67mm minimum. So the closest of these citranges is the Rusk at 51mm which could fit your description.
(Note that in the following picture, the top row shows a trifoliate orange and an immature Rusk citrange.)

Of-course there are plenty of other citranges developed more recently, but I've found it difficult to find photos and information about them.
Mike/Citrange

Thanks Mike. Rusk it must be then.