I'm not sure there is any hard research on this, but atmospheric pressure changes have been implicated in the synchronized blooming of Gethyllis. These South(west) African geophytes bloom during the summer, when there is no rain. Gene Eugene Zielinski Augusta, GA USA > [Original Message] > From: Adam Fikso <adam14113@ameritech.net> > To: <pbs@lists.ibiblio.org> > Date: 9/11/2008 2:52:02 PM > Subject: [pbs] plants that NEED an atmospheric pressure change?? > > Hello All,. Mary Sue's last post caught my eye re the above. Is this a > known , for-sure fact for any plants? It's totally new to me although I've > wondered about it from time to time. Any data-based responses are welcome. > Adam in Glenview, IL. USDA 5a (sort of) > > _______________________________________________ > pbs mailing list > pbs@lists.ibiblio.org > http://www.pacificbulbsociety.org/list.php > http://pacificbulbsociety.org/pbswiki/