Apparently the stomata (tiny 'breathing' pores found abundantly on the reverse side of leaves) of tetraploid lilies are significantly larger than those of diploids. In theory, if you found yourself a good quality botanical hand lens, like the one here (not promoting this site or brand, just using it as an example because I'm not sure how familiar readers are with them!):
https://www.pilbarageology.com...
you could examine your lilies and see if you can note a difference.
Of course that means you need to have a few confirmed diploids and tetraploids already, to compare... and it doesn't help you make a judgement before buying a particular cultivar if you can't find a ploidy reference for it. I admit, when I tried looking I didn't have any confirmed tetraploids and I just squinted at a bunch of my seedlings then gave up because diploid stomata really are so damned small! I should really try examining a few tetraploid leaves next summer so I can see for myself if the stomata are indeed any bigger. Or if my eyesight has improved.
