About your Lily species hybrids list, Joshua, it is definitely a useful tool.
But I don't think the existence of a particular cross in the NALS Seed ex list proves the cross can be by natural means (without embryo rescue or other non-natural methods).
----- Of course, just because a seed has an obvious embryo, doesn't mean it is naturally viable. So even though a seed lot that looks perfectly fine, that doesn't automatically mean the seed can develop into a plant. I would never discourage anyone from sending such "questionable" seed to the seed ex, or from buying them from the seed ex. You can never know for sure. Still, the presence of an embryo just isn't absolute confirmation of continued compatibility.
----- In the case of the crosses involving Aurelian lilies and L. nepalense in the 2015 NALS Seed ex, one might think that since the pollen parent of many of the crosses is already a mature Aurelian x L. nepalense cross¹, that this is proof. But was that previous cross through a natural, ER or some other assisted means? The only way to know would be to talk to the seed donor, Paul Carter. I am not familiar with his name, so I have no basis to assume anything. (Maybe you know more about this and can enlighten?)
Since I donated L. papilliferum that year, I was among the first dibs to obtain a few of those crosses. They did have visible embryos, but with four lots, none produced even one sprout. (Hope it wasn't just me...
)
¹Example: 85-144 Moonlight Belle x (yellow aur. x L. nepalense)
