Hi TG

I only just started growing lilies from seed last winter and planted my first batch outside this summer. So I'm no expert. But, from your description it sounds like you have immediate epigeal (quick growth) seeds that have sprouted producing a root and cotyledon (which without sun would look like just one white strand). If that is the case then plant them in some potting soil with the tops sticking out and put them in a sunny window sill so they can start growing and form their first true leaves. If you have delayed hypogeal seeds they will need a cold spell in the fridge (after 3 months warm temps first).

What types of lilies did the seeds come from? That'll tell you which type of germination you have.

Check out the seed growing page on the North American Lily Society website.

-Helen

Here is a link that might be useful: NALS seed growing page