My first ever lilies I propagated from seed I obtained from Australia - from a Clive Smith at Blue Mountain Liliums in Bilpin New South Wales. This was when I lived in England.
When my wife and I moved to Washington State I started growing from bulbs and then from their seeds, scales and bulbils with great success.
About five years ago I started growing Cardiocrinums, giganteum, & vars. Glehnii and Yunnanense.
I thought I was in heaven when I found how many seeds they generated. My first batch were planted ON a decent potting soil in December and covered them with grit. I left them outside exposed to all the winter weather and in the following Spring there were five seedlings which grew to about 2" and stopped there, I thought developing a bulb underground. However over the next few weeks they gradually turned more and more brown and disappeared. Most disappointing.
I was given a whole stem of giganteum in seed later in the year from a local Botanic garden. From this I planted out maybe about 100 seeds in five separate trays, again leaving them out all over Winter. Nothing happened last Spring, but just four weeks ago one tray produced three of the usual monocots, growing to 2" again. I moved the tray into a cold greenhouse to protect it from wind, heavy rain and worse, but they are still at 2", still holding the seed envelope at their tips. I am thinking of bringing them inside to a warmer atmosphere to see if that will induce some growth.
Last year I purchased a young Cardiocrinum bulb at vast expense - don't tell my wife. I will not bloom for about another three years or more, but I can hardly wait for it to produce, as it is one of very few Pink that were bred by a nursery in Port Townsend. I would like to be successful at raising from seed before it produces it's flowers. The nursery owners assured me that I should leave the trays out in the open as they almost always produced a second large flush of seedlings in the second Spring, although that never happened with that first tray. I have also been told that all Cardio. seeds require a certain amount of exposure to UV light, but nothing was specified. I would think that natural amounts of UV available when the seed blows away from it's pod would work - how else would they propagate naturally?
I am looking forward to next Spring and the five trays I now have waiting. Anybody out there have any experience growing these from seed?

Cardiocrinum seed have a low germination rate. It is said that less than half of what looks like good seed is really not viable at all. Although they are related to Lilium, you can't backlight the seed to see if they contain embryos. (I've tried.) At any rate, they are very erratic germinators in my experience. I've grow Cardiocrinum cordatum. In the late spring after the seeds have experienced their first winter, I think I got about 1% sprouting. Then for three more years, I'd get another 5-10% each year. Sometimes they would put up a second leaf that was no bigger than the original initial cotyledon, but mostly no second leaf at all. I had attributed that to my lack of care, but maybe not? Unfortunately, in my cold climate they were never hardy enough to survive the winters, although the ungerminated seeds had not problem.