Many of the species daylilies are fragrant. I have some fragrant daylilies that you can smell walking the beds, but you will have to sniff out which ones. I grow all types of diploids and have a couple of rows of species crosses. They are still blooming now when most are done.
I like knowing the parents and I do research plants where data is available. I try to keep track of my crosses but don't always get it done. I don't always have time to tag all the flowers before having to leave for work. Sometimes I make notes to tag when I get off work, but there are always ones missed or tags dropped. I make some unusual crosses where you cannot determine parents by looking at the bloom.
Some hybridizers don't keep track of parents and even say it is not worth the efforts. I don't keep track for anyone other than myself. I like to be sure of at least some of the results. I have made crosses where I was confident I would make something, but nothing special resulted. Then I have made crosses for experiment where every seedling was nice.
Also, it is good to know the parents to help make hybridizing decisions. There can always be some trait hiding that may lead you to a certain cross just by knowing the genetics. We made so many seeds this year that if we plant them, there will be lots just marked seedling x seedling. I did not take the time to check all the tags in the ground at seed harvest.
Until we started hybridizing, we had very few to re-bloom. Now we get quite a few seedlings to re-bloom. If I had not marked my crosses, I may not realize that I have 2 seedling lines that re-bloom at a high percentage.