There is something very very strange going on with Citrus indica. It has been genetically tested, and it was found to actually be a tri-hybrid, and not a wild species at all:
C. indica Tan. [ID 7] has a tri-hybrid genome origin according to the Structure analysis (25 % from C. reticulata, 45 % from C. medica and 30 % from Papeda). https://link.springer.com/article/10.1007/s11295-015-0951-1An earlier paper tested a lot of wild and 'cultivated' Citrus indica germplasm, and found that it was a wild species. Furthermore they mention there is a very similar variety called Citrus sp. 'Memang athur', and that one seems to have hybrid origin:
https://ui.adsabs.harvard.edu/abs/2010ScHor.123..350K/abstractSo putting two and two together (not always an advisable thing to do...), it's possible that much or even all of the Citrus indica in cultivation is actually Citrus sp. 'Memang athur', and that was collected by Western researchers accidentally as probably it had more impressive fruits. I sourced Citrus indica (under the tri-hybrid name), and it seems to be polyembryonic, which would mean I also don't have the wild species (assuming it is actually monoembryonic). Also the seeds of what I sourced were the wrong shape for wild described C. indica, being tiny and more like small citron seeds.
