I would expect a 18" DL to have smaller seedlings than a 39" DL, or is that silly?
Not at all.
It quite possibly is the case that on
average smaller daylilies have smaller seeds (and seedlings) than larger daylilies. It is quite possible that on
average daylilies with smaller flowers have smaller seeds (and seedlings) than daylilies with larger flowers.
However, even if there are such relationships between the
average sizes of seeds (and seedlings) and plants it may still be true that seeds (or seedlings) of certain 18" daylilies are larger than the seeds (or seedlings) of certain 39" daylilies.
The (fictitious - used as an example) figure is of the seed sizes of all cultivars (of the same ploidy) that are 18" and all cultivars (of the same ploidy) that are 39". In the figure the average seed size of 18" daylilies is significantly smaller than the average seed size of 39" daylilies. Even though that is the case, as just one example one can look at in the figure, daylilies in the green section of the 18" distribution have seed sizes that are larger than the average seed size of the 39" daylilies and daylilies in the blue section of the 39" distribution have seed sizes that are smaller than the average of the 18" daylilies.