Nathan, this is fascinating! I'm starting to think that seed of Western NA species has a long life expectancy in a dormant state, being able to remain dormant for years in the soil seed bank until the conditions are right (fire?). I've heard of experiments testing seed longevity of Verbascum blattaria, with seed showing almost 100 per cent germ after 100 years of being baried in glass bottles. -Travis Owen Rogue River, OR http://amateuranthecologist.blogspot.com/