Which fruit has the highest content of vitamin C?

Kakadu plum is a plant native to Australia. Used as a traditional bush food and bush medicine for centuries, the fruit has especially high levels of vitamin C.

The Kakadu plum has a high concentration of vitamin C in its fruit: recorded concentrations of 2300–3150 mg/100 g (3.5 ounces) wet weight and occasionally as high as 5300 mg/100 g, compared with 50 mg/100 g (3.5 ounces) for oranges, making it among the highest known of any natural source.

It is a slender, small to medium-sized tree growing up to 14 m (46 ft) in height, with creamy-grey, flaky bark and deciduous pale green leaves. The flowers are small, creamy-white, perfumed.

The fruit is yellow-green, about 2 cm (0.79 in) long and 1 cm (0.39 in) in diameter, almond-sized with a short beak at the tip, and contain one large seed.