Natsumikan

The Natsumikan is a natural hybrid of pummelo (Citrus maxima) and mandarin orange (Citrus reticulata).

The fruit is large (400gr+), slightly flattened and rough-skinned, and juicy when ripe.
This is the Japanese summer grapefruit, picked in April and May for fresh eating.
Kept for a few weeks, it gains even more flavor.

In January and February, it can also be squeezed like a lime.
The juice and especially the aromatic rind (either green or orange when ripe) are used in cooking and jams.

The tree is very productive and vigorous, with no thorns.

References:
https://idtools.org/tools/1076/index.cfm?packageID=1179&entityID=8698https://fr.wikipedia.org/wiki/Natsumikan