Zygotic lemons and/or limes?

[Walt]

II have read that lemons and limes in general have only nucellar seeds.  Are there exceptions? 
I understand that Meyer and  Ponderosa are zygotic but not true lemons,

[pagnr]

West Indian or Key Lime is considered clonal from seed. I've seen a lot of different plants in Nth Qld, including in the wild. The fruit size and shape on individual plants can vary.
Tahiti Lime is essentially seedless. Infrequent seeds that I have grown are fairly variable lime like plants. Some are very weak and never progress. None have fruited yet.
True Lemon seedlings I have grown seem fairly true to type, with some slightly variable.
Rough Lemon produces identical seedlings, suitable for rootstock production. Again if a bunch of Rough Lemon rootstocks sucker and fruit, the fruit can be fairly variable in size and colour ( canary yellow to reddish ).

[Galatians522]

Persian/Tahiti lime is zygotic if you can find a seed. They are typically seedless because they are triploid. Any seed that sets is the result of a revert back to diploid in the gamates.

[Till]

I have picked up somewhere the information that Rough Lemon has a higher degree of zygotic seedlings if the right pollen is applied. If you are interested I can search the book where it stood. Pollen sometimes make the difference. Calamondin for instance is stricly nuccellar but produces a reasonable number of hybrids with Poncirus.