Here's something I guarantee no-one on this forum has ever seen before!
Citrus gracilis - the most recently named citrus species - is a rare species from the tropical north of Australia. After years of trying, I have finally received a picture of an open flower. Sent to me by a keen botanist who works at the Northern Territories Herbarium and is building his own website about Darwin Region Flowers
Citrus gracilis flower:

You saw it here first!
Now, who's got a picture of the fruit?
Mike aka Citrange

Great pic Mike. That is really cool. Look at the bark, it doesn't even look like citrus. I have heard of these before, but never seen them. I believe they are found in New Guinea as well as Australia.

The flower has six petals, citrus are commonly a 5 petaled flower. - Millet (,435-)

The leaves look exactly like Eremocitrus Glauca. Very cool Mike! Thanks!