When a triploid is pollinated with pollen from a diploid (triploid x diploid) , or a diploid is pollinated with pollen from a triploid (diploid x triploid) or a tetraploid is pollinated with pollen from a triploid (tetraploid x triploid) or a triploid is pollinated with pollen from a tetraploid (triploid x tetraploid) the process will begin the same way as for diploid x diploid crosses or tetraploid x tetraploid crosses. A certain percentage of the crosses will "take" - that is the petals and sepals will drop off and a pod will start to form and grow larger. The pod will look good and grow larger for as many as seven to ten days and then usually dry up and fall off. A few pods may stay on the plant and continue to get larger for several more weeks but then dry up and fall off. Very rarely a pod may stay for as long as five weeks and have a viable seed.

Stout cross-pollinated 7,135 flowers of the triploid 'Europa' ditchlily and produced 23 pods that survived to maturity. At the time he wrote his report he had managed to produce only eleven seedlings. Using the pollen from 'Europa' on diploid daylilies was slightly more successful.

This whole triploid thing is cool, especially since I have an unknown daylily that is an older cultivar. I pollinated it with tet and dip and we'll see which ones take. If none of them take, maybe I have a trip? That would help me narrow down what it is.

I assume that trips x trips take easily, right?

If none of my pollinated blooms set pods, maybe I'll ask for some pollen from Dennis' Europa (presumably) plant.

I've had oodles of seed pods on my ditch lilies, and have never had one reach maturity, after many years. I think I dabbed pollen on them once, just because I was walking past them with some pollen, but nothing came of it. The bees are the ones that seem to make all of those pods start to grow, at least for me. I started thinking it was the most fertile daylily ever, until I ended up with zero seeds every year!

DogsNDaylilies said: I pollinated it with tet and dip and we'll see which ones take. If none of them take, maybe I have a trip?

Unfortunately if none take it may just mean that it is sterile as a pod parent (female sterile).

I assume that trips x trips take easily, right?

They may "take", that is set pods but the pods are not likely to survive.

Simplified version:

For both diploids and tetraploids the total number of chromosomes is divisible by two. That means when the plant makes its pollen and ovules it can move a balanced set of its chromosomes to each. When the seed is produced the balanced sets are combined and the seedling has the exact same number of chromosomes as its parents had.

A diploid daylily has 11 pairs of chromosomes - its pollen has 11 chromosomes (one from each pair).
For the sake of this example a tetraploid daylily has 22 pairs of chromosomes - its pollen has 22 chromosomes (one from each pair) - this is a simplified version of what happens in tetraploids - in real life there are complex problems in tetraploids. Some of those problems are similar to those in triploids.

A triploid daylily has 11 triples of each chromosome - its pollen can have anywhere from 11 chromosomes to 22 chromosomes or perhaps even other numbers. The triplet chromosomes cannot be divided evenly and simply for the pollen. The uneven numbers of chromosomes in the pollen and ovule result in uneven numbers in the potential seed and cause problems so that they do not usually develop.