A nursery owner down here in Tasmania once said that they'd given lily seed to someone, only to have that person tell them that nothing had come up - only a lot of grass which they'd carefully weeded out of the pots. So, look for cotyledons that are flat and grass-like (if you're not looking too close). The first true leaves which follow are generally broader, like those produced by small offset bulbs.

Kayman, too funny :-) Excellent story....