Hmmm. Aren't fluoride and chlorine added to drinking water because in low levels they kill bacteria, etc. but are not toxic to larger organisms like humans and animals. I believe Dr. Ed McWilliams conducted some research at TAMU in the early 80's that showed a reduction in rooting of Coleus with increasing salt levels. If I remember correctly, he used sodium chloride as the salt. The assumption was the sodium was the culprit but perhaps chlorine also has a negative effect. The point being, perhaps even low levels of chlorine have a negative effect on germination of some geophytes. This would not explain the germination in the miniature greenhouses in So. Cal. however. At any rate, sounds like 2 great thesis for graduate students to follow up on .. the effect of barometric pressure or the effect of low levels of chlorine and fluoride on germination of geophytes. Boyce Tankersley btankers@chicagobotanic.org