Kathleen Sayce and Fred Biasella asked how you can distinguish viable seed of liliaceous plants such as Lilium, Fritillaria, and Tulipa. It's quite easy. The viable seed in this family invariably has "a tiny straight dark line" (as Kathleen Sayce put it) visible if viewed by transmitted light. The dark line is the embryo, the larger, ever so slightly thick area surrounding the embryo is the endosperm, and the papery margin of the seed is simply the seed coat. To a reasonable extent, you can remove the sterile seeds by the time honored method of winnowing, using your breath or a good breeze outside to blow away the lighter, sterile seeds. But for donations to seed exchanges where it's important to aim for the highest possible quality, you will still have to pick over the residue by hand, removing all seeds which lack a visible embryo or which are malformed. Some kind of backlit surface or a small light table, and a good pair of reading glasses can make this hand picking a lot easier. -- Rodger Whitlock Victoria, British Columbia, Canada Maritime Zone 8, a cool Mediterranean climate on beautiful Vancouver Island http://maps.google.ca/maps/…