Have no idea. Where are you seeing this? What country/state do you live in? I have never seen a "Cumquat", only kumquats. We need a little more to go on to help you out :-) If you can provide a link to this cultivar, that would be helpful.

Patty S.

Well a little googling and I got a link. LOL, this is not a variety, I'm pretty sure.
After all the hyperbole in the ad it seems to be an offer of
300 x mixed orange seeds from an Ebay seller.

There's one born every minute eh?

Here is a link that might be useful: Szechwan Sugar Orange Cumquat

Sounds like basically someone has been saving their seeds after juicing their oranges. And now they're trying to sell them on EBay. Hey, if you can get some money for them, why not, right? :-)

I was wondering that too...